Reflective Functioning Research Articles

Childhood maltreatment, dissociation and borderline personality disorder: Preliminary data on the mediational role of mentalizing in complex post-traumatic stress disorder.

Treatments for borderline personality disorder (BPD) and post-traumatic stress disorder (PTSD) are less effective for patients with co-occurring symptoms of both disorders, who are considered to have complex PTSD (cPTSD), compared with patients with either condition alone. Evidence suggests that co-occurrence of symptoms indicates greater impairment in mentalizing. This study examines evidence for targeting mentalizing when treating individuals with co-occurring symptoms, irrespective of their exposure to developmental trauma and, for the first time, investigates the mediational role of mentalizing in the associations between BPD symptomatology and cPTSD. We identified in a routine clinical service a group of patients with BPD, with or without co-occurring symptoms of PTSD. We hypothesized that patients with co-occurring symptoms and a history of childhood maltreatment will show more severe clinical profiles and greater mentalizing problems, which in turn lead to symptoms consistent with cPTSD. Clinical profiles of 72 patients with BPD (43 with and 29 without co-occurring symptoms of PTSD; mean age in both groups 28 years, 79% and 83% female, respectively) were identified using the Structured Clinical Interview for DSM-IV Axis II Disorders. Patients completed self-report measures of BPD and PTSD symptoms, well-being, dissociation and reflective functioning. Childhood trauma histories were evaluated. Compared with patients with BPD-only, those with co-occurring BPD and PTSD showed greater severity in terms of BPD and dissociative symptoms, met a broader range of BPD diagnostic criteria, had a greater sense of personal worthlessness and self-evaluated their well-being as considerably diminished. This group was also more inclined to recall increased instances of childhood sexual abuse. In a mediation analysis, mentalizing acted as a partial mediator for the relationship between BPD severity and cPTSD, as well as between dissociative symptoms and cPTSD. Interestingly, mentalizing did not mediate the relationship between childhood sexual abuse and cPTSD. Overall, the correlational findings are consistent with an intended focus on mentalizing to treat cPTSD symptoms in individuals who also meet criteria for a diagnosis of BPD.

Correcting for Undercounting of Lightning Flashes by Space‐Based Optical Sensors

AbstractAccurate measurements of global lightning are essential for understanding present and future atmospheric electricity, composition, and climate. The latest space‐based lightning detector, the Geostationary Lightning Mapper (GLM), was the first to be placed in geostationary orbit, with a continuous view of most of the American continents. Prior to the GLM, the Lightning Imaging Sensor (LIS) on the Tropical Rainfall Measuring Mission (TRMM) satellite collected lightning measurements from which numerous lightning climatologies have been developed, including those used in global models. However, this study finds that both the GLM and a second, similar LIS placed on the International Space Station (ISS) in 2017 detect lightning at similar rates and are undercounting lightning compared to ground‐based Lightning Mapping Arrays (LMAs). The GLM undercounts lightning by an average factor of 7.0, reaching a maximum over 120 as a function of satellite zenith angle, radar reflectivity at a height where the temperature is −10°C, flash height, and thunderstorm polarity. The LIS is estimated to undercount lightning by an average factor of 5.6, reaching a maximum of 75.0 as a function of radar reflectivity at the −10°C level, flash height, and thunderstorm polarity. Preliminary predictive equations for the GLM and LIS lightning undercount factor, or scaling factor (SF), use ice‐water content, equilibrium level, flash height, and satellite zenith angle, all of which can be derived in models. These equations are developed to encourage updating lightning parameterizations within global models and will likely increase modeled lightning's effects on atmospheric electrical circuits, composition, chemistry, and climate change.

Structural, electronic, and optical properties of three types Ca3N2 from first-principles study.

To find the potential value of Ca3N2 in the field of optoelectronics, the physical properties of Ca3N2 will be analyzed. It can be concluded from the electronic properties that the Ca-N bonds of α-Ca3N2 are more stable than those of δ-Ca3N2 and ε-Ca3N2. The dielectric function, reflectivity function, and absorption function of three types of Ca3N2 were accurately calculated, and it was concluded that α-Ca3N2, δ-Ca3N2, and ε-Ca3N2 have greater transmittance for visible light and exhibit optical transparency in the near-infrared frequency domain. Combined with the high hardness, strong bonding, high melting point, and wear resistance of Ca3N2, Ca3N2 can be used as a new generation of window heat-resistant materials. The α-Ca3N2, δ-Ca3N2, and ε-Ca3N2 are indirect, direct, and indirect narrow bandgap compounds, respectively, that is, δ-Ca3N2 is more suitable for luminescent materials than α-Ca3N2 and ε-Ca3N2. α-Ca3N2 and δ-Ca3N2 have high reflective properties in the ultraviolet region and can be used as UV protective coatings. All three Ca3N2 materials can be used industrially to synthesize photovoltaic devices that operate in the ultraviolet region. Based on the first-principles of density functional theory calculations, the structures, electronic properties, and optical properties of α-Ca3N2, δ-Ca3N2, and ε-Ca3N2 were calculated. The calculation results show that although the α-Ca3N2, δ-Ca3N2, and ε-Ca3N2 have similar electronic structures, some phases have better properties in some aspects.

Апроксимація дистрибутивної функції відбивної здатності поверхні поліном третього степеня

In the article a bidirectional reflectance distribution function based on a polynomial of the third degree is developed. The main disadvantages of Schlick, Phong, Blinn reflectance models are analyzed. The approximation of Blinn-Phong model by a cubic polynomial is proposed to improve the productivity of three-dimensional image formation. Formulas for the coefficients of the approximation cubic polynomial are calculated. The disadvantages of using the proposed cubic polynomial for reproducing the glare’s attenuation zone are considered. A function for high-precision reproduction of this zone is proposed, formulas of its coefficients are calculated. A combined function, combining a cubic polynomial for reproducing the glare’s epicenter zone and a function for reproducing the attenuation zone, is proposed. The plot of the combined function is built. It is shown that the combined function reproduces the glare’s epicenter and attenuation zones with small relative and absolute errors. The developed reflectance model provides a highly-productive formation of three-dimensional scenes in computer graphics systems. The proposed distribution function of surface reflectivity can be used in computer graphics systems.

Improved Retinex algorithm for low illumination image enhancement in the chemical plant area

Due to the complexity of the chemical plant area at night and the harsh lighting environment, the images obtained by monitoring equipment have issues such as blurred details and insufficient contrast, which is not conducive to the subsequent target detection work. A low illumination image enhancement model based on an improved Retinex algorithm is proposed to address the above issues. The model consists of a decomposition network, an adjustment network, and a reconstruction network. In the decomposition network, a new decomposition network USD-Net is established based on U-Net, which decomposes the original image into illumination and reflection maps, enhancing the extraction of image details and low-frequency information; Using an adjustment network to enhance the decomposed lighting image, and introducing a Mobilenetv3 lightweight network and residual structure to simplify the network model and improve the contrast of the image; In the reconstruction network, the BM3D method is used for image denoising to enhance the ability to restore image detail features; The enhanced illumination and reflection images were fused based on the Retinex algorithm to achieve low illumination image enhancement in the chemical plant area. This article uses five image quality evaluation indicators, namely Peak Signal-to-Noise Ratio, Structural Similarity Index, Natural Image Quality Evaluator, Interpolation Error, and Level of Effort, to compare eight traditional or modern algorithms and evaluate three different types of datasets. The experimental results show that the improved algorithm enhances the texture details of the image, improves the contrast and saturation of the image, and has good stability and robustness, which can effectively meet the needs of low illumination image enhancement in chemical plant areas.

The development of the Psychotherapists' Supervision Preferences Questionnaire—Derived from the Proctor Model

AbstractBackgroundThe Proctor Model describes three core functions of clinical supervision: formative, restorative and normative. While having high face validity as a tool for measuring supervision preferences that can facilitate the formulation of the supervision contract, its construct validity is unclear, and the literature suggests a more all‐encompassing model by including a reflective component.ObjectiveThe aim of this study was to assess the construct validity of the Proctor Model and use these results to develop a short instrument that can facilitate the formulation of the supervision contract.MethodThrough a literature review and expert discussions, a 28‐item inventory was created. After pilot‐testing and revisions, the inventory was administered to 204 psychotherapists. These data were analysed with factor analysis, leading to a revised version that was enrolled in a second sample of 125 psychotherapists.ResultsFactor analysis of the first sample suggested a five‐factor solution as the formative function consisted of two separate constructs: conceptual (receiving role of the therapist and theoretical focus) and experiential (active role of the therapist, skill‐based and feedback‐oriented). The restorative function composed of sharing thoughts and feelings and being validated and recognised. Pre‐theorised restorative items describe an active handling of distressing feelings loaded on the reflective function. Analysis of the second sample confirmed the suggested five‐factor structure and gave support for overall replicated psychometric properties. Regression and correlation analyses showed preliminary evidence for convergent and divergent validity.ConclusionThe results provide a more nuanced understanding of the Proctor Model and provide the field with a psychometrically sound instrument for the formulation of the supervision contract.

Maternal psychological risk and the neural correlates of infant face processing: A latent profile analysis.

Maternal psychological factors, including anxiety, depression, and substance use, may negatively affect parenting. Previous works with mothers have often assessed each of these factors in isolation despite their frequent co-occurrence. Psychological factors have also been associated with neural processing of facial stimuli, specifically the amplitude (i.e., size) and latency (i.e., timing) of the face-specific N170 event-related potential. In the current study, 106 mothers completed measures assessing maternal psychological factors-anxiety, depression, and substance use. A latent profile analysis was used to identify profiles of psychological factors and assess profile associations with the N170 elicited by infant faces and with parental reflective functioning (PRF) as a measure related to caregiving. Two profiles (termed high and low psychological risk) were identified, with the higher risk profile associated with delayed N170 latency responses to infant faces. An exploratory analysis evidenced an indirect effect between the higher psychological risk profile and lower PRF through delayed N170 latency responses to infant faces. Taken together, maternal psychological risk across multiple indicators may together shape neural processing of infant faces, which may have downstream consequences for caregiving.

Prospective clinical validation of the Empatica EmbracePlus wristband as a reflective pulse oximeter.

Respiratory diseases such as chronic obstructive pulmonary disease, obstructive sleep apnea syndrome, and COVID-19 may cause a decrease in arterial oxygen saturation (SaO2). The continuous monitoring of oxygen levels may be beneficial for the early detection of hypoxemia and timely intervention. Wearable non-invasive pulse oximetry devices measuring peripheral oxygen saturation (SpO2) have been garnering increasing popularity. However, there is still a strong need for extended and robust clinical validation of such devices, especially to address topical concerns about disparities in performances across racial groups. This prospective clinical validation aimed to assess the accuracy of the reflective pulse oximeter function of the EmbracePlus wristband during a controlled hypoxia study in accordance with the ISO 80601-2-61:2017 standard and the Food & Drug Administration (FDA) guidance. Healthy adult participants were recruited in a controlled desaturation protocol to reproduce mild, moderate, and severe hypoxic conditions with SaO2 ranging from 100% to 70% (ClinicalTrials.gov registration #NCT04964609). The SpO2 level was estimated with an EmbracePlus device placed on the participant's wrist and the reference SaO2 was obtained from blood samples analyzed with a multiwavelength co-oximeter. The controlled hypoxia study yielded 373 conclusive measurements on 15 subjects, including 30% of participants with dark skin pigmentation (V-VI on the Fitzpatrick scale). The accuracy root mean square (Arms) error was found to be 2.4%, within the 3.5% limit recommended by the FDA. A strong positive correlation between the wristband SpO2 and the reference SaO2 was observed (r = 0.96, P < 0.001), and a good concordance was found with Bland-Altman analysis (bias, 0.05%; standard deviation, 1.66; lower limit, -4.7%; and upper limit, 4.8%). Moreover, acceptable accuracy was observed when stratifying data points by skin pigmentation (Arms 2.2% in Fitzpatrick V-VI, 2.5% in Fitzpatrick I-IV), and sex (Arms 1.9% in females, and 2.9% in males). This study demonstrates that the EmbracePlus wristband could be used to assess SpO2 with clinically acceptable accuracy under no-motion and high perfusion conditions for individuals of different ethnicities across the claimed range. This study paves the way for further accuracy evaluations on unhealthy subjects and during prolonged use in ambulatory settings.

Parental guilt and children's internalizing and externalizing behavior: The moderating role of parental reflective functioning.

The immense responsibility inherent in parenthood makes feeling guilty highly prevalent among parents. Such feelings are natural, yet excessive guilt is related to depression and anxiety and could burden parents. Qualitative research suggested that guilt is predominant in parents whose children suffer from behavioral and emotional difficulties, making it necessary to quantify guilt and examine possible resilience factors that could alleviate the aversive aspects of it. In this study, we examined the association between children's externalizing and internalizing problems and different aspects of parental guilt, assessing whether parental reflective functioning (PRF) would moderate these associations. One hundred six parents of children aged 1.30-9.30 years were recruited from child daycare centers and community clinics. The Parent Development Interview was administered to measure PRF. Based on this interview, we created a new coding system, to quantify three aspects of parental guilt: intensity, reparation, and internal reaction to guilt. Children's difficulties as well as parents' depression and anxiety were assessed using validated self-report measures. We showed that children's difficulties were related to parental guilt, but only when levels of PRF were not high. Specifically, internalizing problems were related to greater intensity and negative internal reaction to guilt only when PRF was low or moderate, and externalizing problems were related to greater intensity of guilt only when PRF levels were low. These findings suggest that encouraging reflective functioning could reduce the burden of guilt. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

A longitudinal study of families created using egg donation: Family functioning at age 5.

Findings are reported from Phase 2 of a longitudinal study of family functioning in heterosexual-couple families with 5 year olds conceived using identity-release egg donation. Seventy-two egg donation families were compared to 50 in vitro fertilization (IVF) families (ethnicity: 93% White British) using standardized observational, interview, and questionnaire measures. There were no differences between family types in the quality of mother-child or father-child interaction, apart from lower structuring by fathers in egg donation families. Egg donation mothers and fathers reported higher levels of parenting stress and lower levels of confidence and competence than their IVF counterparts. Egg donation mothers reported lower social support and couple relationship quality, greater anger toward their child, and perceived their child as more angry and less happy, compared to IVF mothers. Egg donation fathers showed greater criticism and anger toward their child, less joy in parenting, and were less satisfied with the support they received, than IVF fathers. Children in egg donation families showed higher levels of externalizing problems than IVF children as rated by mothers, fathers, and teachers, whereas they were rated as having higher levels of internalizing problems by teachers only. Externalizing problems were predicted by mothers' lower initial social support, steeper increases in parenting stress and greater concurrent criticism, whereas internalizing problems were associated with poorer initial couple relationship quality as rated by mothers. Both were predicted by fewer gains in reflective functioning. There was a moderation effect such that parenting stress was a stronger predictor of externalizing problems for egg donation than IVF families. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

VLT/MUSE Characterization of Dimorphos Ejecta from the DART Impact

We have observed the Didymos-Dimorphos binary system with the MUSE integral field unit spectrograph mounted at the Very Large Telescope before and after DART impact and captured the ensuing ejecta cone, debris cloud, and tails at subarcsecond resolutions. We targeted the Didymos system over 11 nights from 2022 September 26 to October 25 and utilized both narrow- and wide-field observations with and without adaptive optics, respectively. We took advantage of the spectral–spatial coupled measurements and produced both white-light images and spectral maps of the dust reflectance. We identified and characterized numerous dust features, such as the ejecta cone, spirals, wings, clumps, and tails. We found that the base of the sunward edge of the wings, from October 3 to 19, is consistent with maximum grain sizes on the order of 0.05–0.2 mm and that the earliest detected clumps have the highest velocities, on the order of ;10 m s−1. We also see that three clumps in narrow-field mode (8″ × 8″) exhibit redder colors and slower speeds, around 0.09 m s−1, than the surrounding ejecta, likely indicating that the clump is composed of larger, slower grains. We measured the properties of the primary tail and resolved and measured the properties of the secondary tail earlier than any other published study, with first retrieval on October 3. Both tails exhibit similarities in curvature and relative flux; however, the secondary tail appears thinner, which may be caused by lower-energy ejecta and possibly a low-energy formation mechanism such as secondary impacts.

On the question of the dialectic of scientific knowledge in russian philosophy: the problem of reflection

The subject of the study is the phenomenon of reflection in the structure of the mechanisms of scientific cognition. The results of studying the phenomenon obtained within the framework of Russian philosophy in different periods of its development – the Soviet and modern stages - are compared. Attention is drawn to the fundamental nature of the research results of scientific reflection obtained during the Soviet period of philosophy development. In the philosophy of that period, the concept of reflection was proposed, which remained outside the field of view of modern research. A feature of the subject of the Soviet concept is the identification of two aspects of scientific reflection – the relationship between reflection and rationality, as well as the relationship between the meaning-setting and meaning-revealing functions of reflection. The subject of modern domestic research is influenced by the Western tradition. Its characteristic feature is the isolation of reflexive thinking on oneself or, in Soviet terminology, the reduction of scientific reflection to a semantic function. The research method is a dialectical-materialistic approach. The peculiarity of the study is the use of internal contradictions of reflection. The novelty of the work is characterized by the application of the results of Soviet dialectical-materialistic research to modern analysis. It is shown that the modern discussion of this problem is in a dialectical context, constituted by the framework of interrelated opposites. The idea is expressed that the dialectical-materialistic approach continues to be fundamental and is an adequate method of considering reflection. In particular, the dialectical-materialistic methodology will contribute to overcoming, in the words of one of the modern researchers, the "epistemological impasse" with which he characterizes the results of modern study. The conclusion is made about the need to resume dialectical research.

Inflammatory Bowel Disease and Irritable Bowel Syndrome: What Differences in Mentalization Abilities? A Scoping Review

Mentalization is a psychological process that enables individuals to understand the self and others in terms of intentional mental states. The aim of this scoping review was to provide an overview of the findings on mentalization in patients with inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). A literature search, in line with the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols extension for Scoping Review guidelines, was conducted in the following bibliographic databases: PubMed, PsycINFO, and Scopus. Databases were queried using the following strings (with Boolean operators): (“mentaliz*” OR “metacogniti*” OR “theory of mind” OR “ToM” OR “reflective function*”) AND (“irritable bowel syndrome” OR “IBS” OR “inflammatory bowel disease” OR “IBD”). In line with the eligibility criteria, seven articles were included. Results showed that no significant differences in metacognitive ability were found between patients in the IBD and IBS groups. This review revealed the mentalizing difficulties for patients with IBD and IBS. These results should be interpreted with caution since they are based on a few studies that used different instruments to assess mentalizing processes. Future studies are needed to clarify the role of mentalization in patients with these gastrointestinal conditions.

Behind the screens: Proposing a mentalization-based theoretical model of problematic Internet use

Problematic Internet Use (PIU), with its adverse health outcomes, is a clinically established phenomenon that is not formally diagnosable yet. The latest PIU research reveals differential psychological mechanisms underlying two types of Internet usage: social use (like using social media, chatrooms, and others) and non-social use (like live streaming, short-form video viewing, and others). Social forms of PIU often signal underlying interpersonal issues, including loneliness, attachment problems, and social skill deficits. In comparison, non-social usage might indicate emotion regulation problems, including emotion recognition deficits, poor cognitive empathy, and emotion suppression. A common developmental concomitant of these functions is the ability to mentalize, operationalized as Reflective Functioning (RF). While studies supporting the role of impaired RF in problematic social uses of the Internet abound, only a few studies relating RF deficits to non-social PIU are identifiable. Also, mentalizing is multidimensional, with cognitive and affective poles influencing emotion regulation and interpersonal functioning. Deficits in both poles of mentalizing have been differentially implicated in non-social and social PIU. Based on the latest empirical evidence in Internet-use problems, the multifaceted role of mentalizing could be meaningfully assimilated into a novel social-cognitive model of PIU. To that end, the current paper attempts to theoretically integrate affective and cognitive mentalizing, with its roles in emotion regulation and interpersonal functioning, into Bandura’s Social-Cognitive Theory of PIU. The theoretical model might have implications in developing a mentalization-based treatment modality for PIU that could train individuals in efficiently regulating emotions and navigating real-life social situations without resorting to an over-involvement with the virtual world.

To be a freshman during the COVID-19 pandemic: A cross-lagged model of depression, mentalizing, and epistemic trust.

Research has shown that severity of depression increased in freshmen during their first months at university due to increased social and academic pressures. Since the start of the COVID-19 pandemic, several cross-sectional studies have suggested that levels of depression in university students are higher than before the pandemic, but longitudinal data are largely lacking. This study investigated severity of depression and negative affect linked to the pandemic among freshmen during their first semester at a large university in Flanders, Belgium. We also investigated whether epistemic trust predicted severity of depression and pandemic-related negative affect and whether problems with reflective functioning (or mentalizing) mediated these relations. Participants in this two-wave prospective study were 289 first-year students of the Faculty of Psychology and Educational Sciences of a large Belgian university. We conducted paired samples t-tests and cross-panel analysis to answer the research question. The number of students at risk of clinical depression increased by 41% between T1 (early October 2020) and T2 (late December 2020). Epistemic mistrust at T1 was prospectively associated with an increase in the prevalence and severity of depression at T2. Problems with mentalizing and negative COVID-19-related affect were positively associated with severity of depression at T2 and mediated the association between epistemic mistrust and severity of depression at T2. The findings highlight the key role of epistemic trust in the development of depression among freshmen, with the COVID-19 pandemic presenting an additional source of uncertainty.

A depth iterative illumination estimation network for low-light image enhancement based on retinex theory

Existing low-light image enhancement techniques face challenges in achieving high visual quality and computational efficiency, as well as in effectively removing noise and adjusting illumination in extremely dark scenes. To address these problems, in this paper, we propose an illumination enhancement network based on Retinex theory for fast and accurate brightening of images in low-illumination scenes. Two learning-based networks are carefully constructed: decomposition network and enhancement network. The decomposition network is responsible for decomposing the low-light input image into the initial reflectance and illumination map. The enhanced network includes two sub-modules: the illumination enhancement module and the reflection denoising module, which are used for efficient brightness enhancement and accurate reflectance. Specially, we have established a cascaded iterative lighting learning process and utilized weight sharing to conduct accurate illumination estimation. Additionally, unsupervised training losses are defined to improve the generalization ability of the model. The proposed illumination enhancement framework enables noise suppression and detail preservation of the final decomposition results. To establish the efficacy and superiority of the model, on the widely applicable LOL dataset, our approach achieves a significant 9.16% increase in PSNR compared to the classical Retinex-Net, and a remarkable enhancement of 19.26% compared to the latest SCI method.

Adaptation and Reflection in the Transition to Parenthood for Women With Risk Factors for Early Parenting Difficulties Who Participated in the STAR Mums Program

The Supporting Transitions and Relationships (STAR Mums) program was developed in response to the clinical need for psychological intervention in pregnancy where mothers have risk factors for difficulties in the transition to parenthood. The program focuses on the developing relationship between the mother and the unborn child and aims to facilitate the normal psychological processes that are known to occur in pregnancy to prepare for the relationship with the infant and to reduce risk factors that may negatively impact this relationship. This article reports on interview data from the final follow-up of 12 high-risk participants at 12 to 14 weeks postpartum regarding their transition to parenthood and aspects of parental reflective function. These women presented with issues in developing their maternal identity and representation in the context of difficulties processing their own difficult childhood experiences. They also demonstrated some issues with limited reflective capacity in their understanding of their infant’s emotional world and experiences. Though there are ongoing issues for these women, they provided feedback that the STAR Mums program included valued discussion around the changes in both self and relationships involved in parenting that helped them to prepare for their experiences of early parenthood by supporting their wondering about the baby and the changes that this new relationship may bring for them as a parent.

The quest for optimal photovoltaics: A theoretical exploration of quasi-one-dimensional tin based chalcogenides XSnS[formula omitted] (X=Ba, Sr)

Structural, mechanical, electronic, and optical properties of alkaline metals (Ba, Sr) tin chalcogenide were investigated by the first principles method based on density functional theory (DFT) implemented in the WEIN2K program. The study found that both materials exhibit a quasi-one-dimensional nature along the b-axis, and the optimized structure agrees with the available experimental data. Mechanical properties revealed that both materials are mechanically stable, exhibit ductility, and have significant anisotropy. BaSnS3 and SrSnS3 exhibit an indirect band gap with the values of 1.55 eV and 1.39 eV, respectively. Which is favorable for photovoltaic solar cell absorber materials. Like many ternary metal chalcogenides, XSnS3 compounds show significant anisotropy in the optical properties due to their quasi-one-dimensional structure. This work determined the degree of optical anisotropy of XSnS3 in terms of the dielectric function, refractive index, optical absorption, reflectivity, optical extinction, birefringence, and energy loss function. The results indicate that BaSnS3 and SrSnS3 materials possess notable optical anisotropy and a high absorption coefficient (α≈106 cm−1), low reflectivity and energy loss function within the visible and ultraviolet energy range. It indicates their potential for use in a range of applications, such as sensors, optoelectronics, and photovoltaic solar cell absorber materials.

Physical properties of Be-based fluoroperovskite compounds XBeF3 (X = K, Rb): a first-principles study

In this study, we used the ab-initio computational tools as implemented in the CASTEP code to explore the effects of pressure on the structural, elastic, electronic, thermodynamic and optical properties of the fluoroperovskite compounds XBeF3 (X = K, Rb) based on Being. Exchange–correlation interactions were modeled using the GGA-PBEsol functional. The ground state of the title materials was characterized by calculating the optimized lattice parameter, the bulk modulus B and its pressure derivative, and the Goldsmith tolerance factor. These materials exhibit structural stability in the cubic structure even when subjected to significant pressure levels, extending up to 18 GPa. The analysis of numerical assessments of single-crystal elastic constants (Cij ), polycrystalline elastic moduli, namely shear modulus (G), Young’s modulus and Poisson’s ratio, as well as the anisotropy factor (A), highlights the mechanical stability, elastic anisotropy and ductility of considered the compounds. The thermodynamic properties of these materials were studied through the Debye quasi-harmonic model. Analysis of energy band structures and density of states spectra shows that XBeF3 (X = K, Rb) is insulating in nature, with band gaps of 7.99 and 7.26 eV, respectively. Additionally, we calculated the linear optical spectra, including dielectric function, absorption coefficient, refractive index, optical reflectivity, and energy loss function. Based on the results obtained, these materials could be used in various optoelectronic devices operating in the UV spectrum and in energy storage devices.

Exploring the physical properties of Ae2TlCoF6 (Ae = Rb, Cs) double perovskites for solar cell applications by first-principles calculations

In this study, we have determined the structural, electronic, optical, mechanical, and thermoelectric properties of Ae2TlCoF6 (Ae = Rb, Cs) double perovskite materials using the density functional theory (DFT). The phonon dispersion curves and formation energy shows that both the materials are dynamically stable and experimentally can be synthesized. The electronic band structure exhibits the semiconductor nature of both materials with direct energy band gap values of 1.35 eV and 1.64 eV for Rb2TlCoF6 and Cs2TlCoF6, respectively. The calculated optical properties of both studied materials exhibit remarkable properties such as high absorption coefficients, low reflectivity, and minimum energy loss function. The calculation of thermoelectric properties shows that Cs2TlCoF6 is a potential thermoelectric material with an improved electronic figure of merit of 0.14 at 800 K, which increases with temperature to a value of 0.25 at 1000 K. We have also investigated the efficiency of our perovskite materials by using the spectroscopic limited maximum efficiency (SLME). The computed results strongly suggest that Ae2TlCoF6 (Ae = Rb, Cs) compounds hold great promise as potential candidates for solar cellapplications.