Theory Of Dissociation Research Articles

Dissociation of HCl into Ions on Wet Hydroxylated (0001) α-Quartz

The acidification of surfaces in the natural and built environments is important to atmospheric science because the process can enhance chemistry at surfaces and increase the release of highly reactive products into the gas phase. We present the results of an ab initio molecular dynamics study using density functional theory of HCl ionic dissociation on the hydroxylated (0001) α-quartz surface. We observed that at temperatures in the range of 250–300 K, HCl ionizes rapidly on a surface wetted with a water monolayer. It seems that ionization is enhanced by lattice mismatch between the silica and water layer. The first proton transfer to a neighboring water molecule initiates proton migration within the water adlayer via the Grotthuss mechanism. Spectroscopic signatures for the ionization are calculated and are in fair agreement with experiment.

Adaptive and maladaptive attraction to negative emotions in music

Individual differences were investigated in an attempt to explain why some people are attracted to negative emotion (grief, sadness) in music. A 10-item Like Sad Music Scale (LSMS) was developed (Cronbach’s α = .802) and compared against subscales measuring absorption, music empathy, rumination, reflectiveness and nostalgia-proneness. This was tested via an online survey, completed by 137 participants. It was hypothesized that absorption and reflectiveness would be correlated with the enjoyment of sad music and rumination would be correlated with an attraction to sad music although not necessarily an enjoyment of it. Consistent with previous findings, absorption was a good predictor of the LSMS and was particularly correlated with the enjoyment of strong emotions in connection with sad music. Rumination correlated with LSMS items ‘helps release sadness’ and ‘can relate to sadness’ while reflectiveness correlated with the item ‘I often find myself grieving as a result of listening to sad music’. These correlations suggest both adaptive and maladaptive uses of sad music for mood manipulation. The results were presented with respect to the dissociation theory of aesthetic enjoyment, where participants with the capacity to enter states of absorption are able to deactivate displeasure circuits and hence enjoy negative emotion in music.

Solution phase thermodynamics of strong electrolytes based on ionic concentrations, hydration numbers and volumes of dissolved entities

This article summarizes the successful restoration of Arrhenius’ theory of electrolytic dissociation founded 130 years ago. His idea of using the conductivity ratio for the degree of dissociation was a breakthrough in interpreting the properties of dilute solutions. For higher concentrations, as it was not satisfactory, attempts were being made to improve the methods of obtaining the degrees of dissociation. However, the latter was prematurely replaced by the empirical activity coefficient correction factors. Subsequently, the success of the Debye–Huckel (D–H) theory of inter-ionic interaction between free ions in explaining the properties of dilute solutions was taken to mean complete dissociation at all concentrations and interpretation of solution properties amounted to extending the D–H equations by the gradual addition of more parameters. At the end of six decades the equations became so complex that they failed to provide a unified interpretation of the causes of non-ideality at all concentrations and a molecular insight into the observed phenomena. Therefore, the present author abandoned them and started investigating the available experimental data as such. Using the degrees of dissociation and surface and bulk hydration numbers evaluated from solution vapour pressures, the author was able to interpret solution properties based on the idea due to Arrhenius a century earlier. Presented here is a comparison of the complicated equations based on complete dissociation with the simple equations obtained based on partial dissociation, hydration and volumes of entities in the solution. All the main equations are summarized in the table.

Dissociation and Identity Transformation in Female Survivors of the Genocide Against the Tutsi in Rwanda: A Qualitative Research Study

This qualitative research study deals with female survivors of the 1994 genocide against the Tutsi in Rwanda. It examines dissociation and identity change in these women before, during, and after the genocide. Three theories were used to frame the findings. The 1st was assumptive world theory (R. Janoff-Bulman, 1992), which postulates that traumatic events may shatter people's everyday assumptions about the world. The 2nd was catastrophic dissociation theory (G. Boulanger, 2007), which refers to the gradual breakdown of the self as it repeatedly “experiences its psychic foundations in ways that do not happen in the average expectable life” (G. Boulanger, 2008,p. 646). The 3rd was structural dissociation theory (O. Van der Hart, E. R. S. Nijenhuis, & K. Steele, 2006), which postulates that when people encounter events that they cannot integrate into their mental lives, their personality may fragment and divide. The data were transcripts of interviews with 30 female genocide survivors. Data analysis revealed that these women experienced trauma-induced identity transformations. Before the genocide, they existed as a “Civilized Self,” with a stable identity in a secure, assumptive world. During the genocide, they existed as a “Survivor Self,” the massive trauma of the genocide having disrupted their prior self-experience and identity. After the genocide, they existed as an “Aftermath Self,” in which their Civilized and Survivor Selves coexisted in an unintegrated, dissociated form. The authors are grateful to Foundation Rwanda for providing them with the interview material and to the Rwandan survivors who shared their stories.

Development of a molecular-dynamics-based cluster-heat-capacity model for study of homogeneous condensation in supersonic water-vapor expansions

Supersonic expansions to vacuum produce clusters of sufficiently small size that properties such as heat capacities and latent heat of evaporation cannot be described by bulk vapor thermodynamic values. In this work the Monte-Carlo Canonical-Ensemble (MCCE) method was used to provide potential energies and constant-volume heat capacities for small water clusters. The cluster structures obtained using the well-known simple point charge model were found to agree well with earlier simulations using more rigorous potentials. The MCCE results were used as the starting point for molecular dynamics simulations of the evaporation rate as a function of cluster temperature and size which were found to agree with unimolecular dissociation theory and classical nucleation theory. The heat capacities and latent heat obtained from the MCCE simulations were used in direct-simulation Monte-Carlo of two experiments that measured Rayleigh scattering and terminal dimer mole fraction of supersonic water-jet expansions. Water-cluster temperature and size were found to be influenced by the use of kinetic rather than thermodynamic heat-capacity and latent-heat values as well as the nucleation model.

Emotion in Popular Music: A Psychological Perspective

This article discusses the role of emotion in popular music from a psychological perspective. An online study was conducted in which 100 young adults made emotion ratings of loved and hated pieces of music. While the literature presents us with some ambiguous views about the function and value of emotion in popular music, the results of the study suggest that for listeners, emotion in popular music is as important as that reported in other musical forms, such as high-art (classical) music, where emotion is considered by many scholars to be more unambiguously important. However, overall popular music was reported to both express and evoke lower passive emotion ratings than high-art music. A corollary of the study is that popular music could be defined by frequency of reported enjoyment of spontaneously selected pieces. As a result Chopin becomes a popular music composer to the same extent that Lady Gaga is a popular performer. The results of the study are interpreted from a psychological perspective, calling upon mere exposure theory to explain how music becomes popular from a listener’s cognitive perspective, and dissociation theory, to explain why negative emotion in popular music can be enjoyed.

В. Ю. Чаговець – перший мембранолог України: життєвий і творчий шлях

Vasyl Chagovets was first to apply the theory of electrolytic dissociation in electrophysiology, formulated the ionic theory of origin of bioelectric potentials and condenser theory of electric irritation of living tissues. He proposed using electrogastrogram as a research method of secretory function of stomach. He first by grounded expedience of application of mathematical methods in biology. Keywords: V. Yu. Chagovets, condenser theory of excitation, bioelectrogenesis.

Dissociative part-dependent biopsychosocial reactions to backward masked angry and neutral faces: An fMRI study of dissociative identity disorder

ObjectiveThe Theory of Structural Dissociation of the Personality (TSDP) proposes that dissociative identity disorder (DID) patients are fixed in traumatic memories as “Emotional Parts” (EP), but mentally avoid these as “Apparently Normal Parts” of the personality (ANP). We tested the hypotheses that ANP and EP have different biopsychosocial reactions to subliminally presented angry and neutral faces, and that actors instructed and motivated to simulate ANP and EP react differently.MethodsWomen with DID and matched healthy female actors (CON) were as ANP and EP (DIDanp, DIDep, CONanp, CONep) consecutively exposed to masked neutral and angry faces. Their brain activation was monitored using functional magnetic resonance imaging. The black-and-white dotted masks preceding and following the faces each had a centered colored dot, but in a different color. Participants were instructed to immediately press a button after a perceived color change. State anxiety was assessed after each run using the STAI-S. Final statistical analyses were conducted on 11 DID patients and 15 controls for differences in neural activity, and 13 DID patients and 15 controls for differences in behavior and psychometric measures.ResultsDifferences between ANP and EP in DID patients and between DID and CON in the two dissociative parts of the personality were generally larger for neutral than for angry faces. The longest reaction times (RTs) existed for DIDep when exposed to neutral faces. Compared to DIDanp, DIDep was associated with more activation of the parahippocampal gyrus. Following neutral faces and compared to CONep, DIDep had more activation in the brainstem, face-sensitive regions, and motor-related areas. DIDanp showed a decreased activity all over the brain in the neutral and angry face condition. There were neither significant within differences nor significant between group differences in state anxiety. CON was not able to simulate genuine ANP and EP biopsychosocially.ConclusionsDID patients have dissociative part-dependent biopsychosocial reactions to masked neutral and angry faces. As EP, they are overactivated, and as ANP underactivated. The findings support TSDP. Major clinical implications are discussed.

Dissociation of the Personality and EMDR Therapy in Complex Trauma-Related Disorders: Applications in the Stabilization Phase

As proposed in a previous article in this journal, eye movement desensitization and reprocessing (EMDR) clinicians treating clients with complex trauma-related disorders may benefit from knowing and applying the theory of structural dissociation of the personality (TSDP) and its accompanying psychology of action. TSDP postulates that dissociation of the personality is the main feature of traumatization and a wide range of trauma-related disorders from simple posttraumatic stress disorder (PTSD) to dissociative identity disorder (DID). The theory may help EMDR therapists to develop a comprehensive map for understanding the problems of clients with complex trauma-related disorders and to formulate and carry out a treatment plan. The expert consensus model in complex trauma is phase-oriented treatment in which a stabilization and preparation phase precedes the treatment of traumatic memories. This article focuses on the initial stabilization and preparatory phase, which is very important to safely and effectively use EMDR in treating complex trauma. Central themes are (a) working with maladaptive beliefs, (b) overcoming dissociative phobias, and © an extended application of resourcing.

A Comparison of the Effects of Amide and Acid Groups at the C-Terminus on the Collision-Induced Dissociation of Deprotonated Peptides

The dissociative behavior of peptide amides and free acids was explored using low-energy collision-induced dissociation and high level computational theory. Both positive and negative ion modes were utilized, but the most profound differences were observed for the deprotonated species. Deprotonated peptide amides produce a characteristic c(m-2)(-) product ion (where m is the number of residues in the peptide) that is either absent or in low abundance in the analogous peptide acid spectrum. Peptide acids show an enhanced formation of c(m-3)(-); however, this is not generally as pronounced as c(m-2)(-) production from amides. The most notable occurrence of an amide-specific product ion is for laminin amide (YIGSR-NH(2)) and this case was investigated using several modified peptides. Mechanisms involving 6- and 9-membered ring formation were proposed, and their energetic properties were investigated using G3(MP2) molecular orbital theory calculations. For example, with C-terminal deprotonation of pentaglycine amide, formation of c(m-2)(-) and a 6-membered ring diketopiperazine neutral requires >31.6 kcal/mol, which is 26.1 kcal/mol less than the analogous process involving the peptide acid. The end group specific fragmentation of peptide amides in the negative ion mode may be useful for identifying such groups in proteomic applications.

Mathematical Model and Simulation of Gas Hydrate Reservoir Decomposition by Depressurization

The numerical model for the depressurization of methane hydrates in a confined reservoir is presented based on mass conservation in porous media, incorporating multiphase flow theory and kinetics of gas hydrate dissociation. The universal implicit difference method is adopted, and the corresponding computer program is developed. During the production of the hydrate reservoir, distribution and the physical changes are analyzed and the gas hydrate dissociation and gas production law are studied from the computation. A numerical simulation shows that the reservoir pressure is descending slowly, which benefits the stabilization of the reservoir and inevitably decreases the efficiency in the production of gas hydrates in the depressurizing process. The gas production rate is controlled by the well pressure. The results are presented to show how this model may be used to estimate a lower downhole pressure of the well for hydrate recovery and how these results depend on reservoir and hydrate properties.

Evaluation of the evidence for the trauma and fantasy models of dissociation.

The relationship between a reported history of trauma and dissociative symptoms has been explained in 2 conflicting ways. Pathological dissociation has been conceptualized as a response to antecedent traumatic stress and/or severe psychological adversity. Others have proposed that dissociation makes individuals prone to fantasy, thereby engendering confabulated memories of trauma. We examine data related to a series of 8 contrasting predictions based on the trauma model and the fantasy model of dissociation. In keeping with the trauma model, the relationship between trauma and dissociation was consistent and moderate in strength, and remained significant when objective measures of trauma were used. Dissociation was temporally related to trauma and trauma treatment, and was predictive of trauma history when fantasy proneness was controlled. Dissociation was not reliably associated with suggestibility, nor was there evidence for the fantasy model prediction of greater inaccuracy of recovered memory. Instead, dissociation was positively related to a history of trauma memory recovery and negatively related to the more general measures of narrative cohesion. Research also supports the trauma theory of dissociation as a regulatory response to fear or other extreme emotion with measurable biological correlates. We conclude, on the basis of evidence related to these 8 predictions, that there is strong empirical support for the hypothesis that trauma causes dissociation, and that dissociation remains related to trauma history when fantasy proneness is controlled. We find little support for the hypothesis that the dissociation-trauma relationship is due to fantasy proneness or confabulated memories of trauma.

Electrophysiological correlates of enhanced perceptual processes and attentional capture by emotional faces in social anxiety

Behavioural studies have used spatial cueing designs extensively to investigate emotional biases in individuals exhibiting clinical and sub-clinical anxiety. However, the neural processes underlying the generation of these biases remain largely unknown. In this study, people who scored unusually high or low on scales of social anxiety performed a spatial cueing task. They were asked to discriminate the orientation of arrows appearing at the location previously occupied by a lateralised cue (consisting of a face displaying an emotional or a neutral expression) or at the empty location. The results showed that the perceptual encoding of faces, indexed by P1, and mobilisation of attentional resources, reflected in P2 on occipital locations, were modulated by social anxiety. These modulations were directly linked to the social anxiety level but not to trait anxiety. By contrast, later cognitive stages and behavioural performances were not modulated by social anxiety, supporting the theory of dissociation between efficiency and effectiveness in anxiety.

Non-Onsager mechanism of long-wave photogeneration in amorphous selenium at high electric fields

The quantum efficiency of the free-carrier-photogeneration in amorphous selenium avalanche blocking structures is studied experimentally in a wide range of wavelengths (380–600 nm) at high electric fields (10−112.5Vμm−1). While at comparatively small excitation wavelengths (up to ≃540nm), our experimental results are consistent with the Onsager theory of electron-hole pair dissociation [L. Onsager, Phys. Rev. 54, 554 (1938)], at larger wavelengths (540–600 nm) and high electric fields Onsager theory fails to explain our results. The reason for the failure of the Onsager approach is discussed and an alternative theoretical tool is adopted to account for the experimental observations.

Reply to Commentaries

The three respondents are discussed separately. In my disagreement with Dr. Bass, emphasis is placed on his contention that I am informed by the classical conflict model. I underline the fact that the purpose of the paper under discussion is precisely to provide a theory of therapeutic action in direct opposition to such a model. It is argued that Dr. Bass' alternative, that relationalists only engage “what is,” represents neither an accurate statement for the relational movement as a whole nor a cogent theory of therapeutic action. In opposition to Bass, the importance of creating an open space for the patient's creation of new ways of being is affirmed. Dr. Williams' comments are addressed from the viewpoint of our differences in assessing levels of pathology and developmental arrest. Comparisons are made between Williams' approach, my more Winnicottian influenced ideas, and the relational position on development and therapeutic action. Agreement is affirmed with Dr. Ceccoli's views that the potential space of the analytic process can be used for the creation of new meaning. Our disagreement lies in her belief that dissociative theory in itself provides such a space whereas I believe it needs to be supplemented with the concept of potential space.

Application of the dissociative electron transfer theory and its extension to the case of in-cage interactions in the electrochemical reduction of arenesulfonyl chlorides

Important aspects of the electrochemical reduction of a series of substituted arene sulfonyl chlorides are investigated. An interesting autocatalytic mechanism is encountered where the starting material is reduced both at the electrode and through homogeneous electron transfer from the resulting sulfinate anion. This is due to the homogenous electron transfer from the two-electron reduction produced anion (arene sulfinate) to the parent arene sulfonyl chloride. As a result, the reduction process and hence the generated final products depend on both the concentration of the substrate and the scan rate. A change is also observed in the reductive cleavage mechanism as a function of the substituent on the phenyl ring of the arene sulfonyl chloride. With 4-cyano and 4-nitrophenyl sulfonyl chlorides a "sticky" dissociative ET mechanism takes place where a concerted ET mechanism leads to the formation of a radical/anion cluster before decomposition. With other substituents (MeO, Me, H, Cl, and F) a "classical" dissociative ET is followed, where the ET and bond cleavage are simultaneous. The dissociative electron transfer theory, as well as its extension to the case of strong in-cage interactions between the produced fragments, along with gas phase chemical quantum calculations results helped us to rationalize both the observed change in the ET mechanism and the occurrence of the "sticky" dissociative ET mechanism. The radical/anion pair interactions have been determined both in solution as well as in the gas phase. The study also shows that despite the low magnitude of in-cage interactions in acetonitrile compared to the gas phase their existence strongly affects the dynamics of the involved reactions. It also shows that, as expected, these interactions are reinforced by the existence of strong electron-withdrawing substituents. The occurrence of an autocatalytic process and the existence of the radical/anion interaction may explain the differences previously observed in the reduction of these compounds in different media.

Laser control of the low-temperature e −+O 2 + reaction

The dissociative recombination theory of slow electrons with molecular ions in a strong monochromatic light field is developed. Classifications of all possible transitions and reaction mechanisms are presented. The potential energy curves of the oxygen molecule O2** dissociative states and partial cross sections are calculated.

Arrhenius' theory of partial dissociation and hydration of electrolytes in solutions replaces existing activity concepts

AbstractThe author shows that Arrhenius's theory of partial electrolytic dissociation was immaturely displaced about eight decades ago by the empirical concept of ionic activities and the assumption of complete dissociation of electrolytes at all concentrations. The latter brought the theory of electrolytes over the next decades into a complicated state without any physical significance. Therefore, the author started a systematic investigation of the available data and could completely restore the original theory of partial dissociation. Now solution properties can be easily understood and quantitatively explained in terms of absolute concentrations and volumes of ions and ion pairs and hydration.

Partial Dissociation and Hydration Quantitatively Explain the Properties of Aqueous Electrolyte Solutions and hence Empirical Activity Concepts are Unnecessary

AbstractThe author shows that Arrhenius's theory of partial electrolytic dissociation was immaturely displaced about eight decades ago by the empirical concept of ionic activities and the assumption of complete dissociation of electrolytes at all concentrations. The latter brought the theory of electrolytes over the next decades into a complicated state without any physical significance. Therefore, the author started a systematic investigation of the available data and could completely restore the original theory of partial dissociation. Now solution properties can be easily understood and quantitatively explained in terms of absolute concentrations and volumes of ions and ion pairs and hydration.

Detailed Kinetics of the Fischer–Tropsch Synthesis on Cobalt Catalysts Based on H-Assisted CO Activation

A complete mechanistic kinetic model of the Fischer–Tropsch synthesis (FTS) over a Co/Al2O3 state-of-the-art catalyst is developed here under conditions relevant to industrial operation. On the basis of the most recent findings on the reaction mechanism, here described according to the H-assisted CO dissociation theory and the alkyl chain growth mechanism, and on the basis of the latest indications available on the rate determining step involved in the CO activation process, rate expressions for all the steps leading to CO and H2 consumption and n-paraffins, α-olefins and H2O formation are derived. Such expressions are functions of the molar fraction of CO, H2 and olefins in the liquid phase surrounding the catalyst pellets, that in turn are related to the gas-phase pressure and composition, and of the surface coverage of the adsorbed species. Thermodynamic and kinetic parameters involved in the model are estimated by non-linear multi-response regression on a complete set of FTS experimental data collected in a lab-scale tubular reactor at steady-state conditions (P = 8–25 bar, T = 210–235 °C, H2/CO feed ratio = 1.8–2.7 mol mol−1, GHSV = 2,000–7,000 cm3(STP) h−1 gcat−1). Both the experimental CO conversion and the hydrocarbon distribution (up to N = 50) in FTS are well predicted by the model with 13 adaptive parameters, without the need of introducing any empirical parameter. Analysis of the model offers insight in the rates of the elementary steps associated with the reaction mechanism and in the surface coverages of the adsorbed species. Such information explains the peculiar reactivity observed over cobalt-based Fischer–Tropsch catalysts, and can provide guidelines for the design of more active and selective catalytic materials.