Lifetime Values Research Articles

Evaluated Material Attractiveness of Plutonium Composition from Economic Simplified Boiling Water Reactor (ESBWR)

The potential for misuse of nuclear fuel has prompted many to make efforts to prevent a country from acquiring nuclear explosive devices (weapons). Weapon utility equated with nuclear material attractiveness when applied to protection and security. Material attractiveness evaluated using an equation first developed by Masaki Saito, namely ATTR. ESBWR is one of the reactors of the BWR reactor type that is still operating. The purpose of this study is to evaluate Material Attractiveness based on the composition of plutonium in the ESBWR reactor, during reactor operation and after reactor operation. The ATTR concept utilizes the plutonium isotope composition to evaluate the material attractiveness aspect. Parameters such as BCM, Rossi-alpha, and neutron prompt life become additional aspects in evaluating material attractiveness. In the research results, the ATTR value decreased from the beginning of reactor operation until the reactor stopped operating. At the beginning of the reactor operation, it was categorizing as a weapon-grade with an ATTR value of 0.19 and when the reactor stopped operating it was categorizing as an unusable grade with an ATTR value of 0.012. At the time of cooling time up to 1x106 (one million) cooling time, the ATTR value increases by 0.019 which was categorizing as an unusable grade. After a cooling time of 1x106 (one million) years up to 1x107 (ten million) years, the ATTR value was 0.001 which categorized as an exempt level. This states that the increasing burnup value will further reduce the ATTR value. Likewise with the Rossi-Alpha and Bare Critical Mass values. Conversely, it will decrease the value of neutron lifetime. The ATTR value after the reactor operates up to one hundred years of cooling time increases and then decreases significantly after 1x106 (one million) years due to the half-life of plutonium isotopes. Likewise, the Rossi-Alpha and Bare critical mass values. However, it is different with the neutron fast lifetime.

Structural, thermal and spectroscopic properties of Er2O3-doped oxyfluoro tellurophosphate glasses

Employing the melt quench method, the oxyfluoro tellurophosphate glasses (PTBMEr), doped with varying erbium concentrations, were prepared. Their physical, structural, optical, and luminescent characteristics were investigated using XRD, EDX, FTIR, absorption and Photoluminescence studies. The amorphous nature and elemental composition were identified using the XRD and EDX spectra. The J-O parameters and radiative parameters, including energy gap (ΔE), branching ratio (βR), radiative lifetime (τrad), and radiative transition probability (AR), were established for different excited levels of erbium in PTBMEr glass matrices. The visible emission spectra were acquired through excitation at a wavelength of 377 nm, resulting in a highly pronounced emission band at 544 nm, corresponding to the transition 4S3/2→ 4I15/2. The NIR emission spectra obtained through excitation at 980 nm showed a prominent broad emission band at 1534 nm pertaining to the transition 4I13/2→4I15/2. Within the set of prepared samples, the PTBMEr05 sample exhibits highest stimulated emission cross section of 0.75 × 10-20 cm2 for the transition 4S3/2→4I15/2. It also exbited superior parameters for the transition 4S3/2→4I15/2 including a stimulated emission crosssection of 1.19 × 10-20 cm2, gain bandwidth of 64.87 × 10-25 cm3, and optical gain of 53.41 × 10-24 cm2s. Experimental lifetime values for the excited level 4I13/2 of erbium in PTBMEr glasses were calculated and found to decrease with concentration due to non-radiative mechanisms and concentration quenching. These results reflect that PTBMEr05 glass is best suited for green laser emission devices and optical fiber communication windows.

Synthesis and photoluminescence properties of high color purity red emitting Li2MgTi3O8:Eu3+ phosphors for warm W-LEDs

In search of efficient and suitable phosphors for white light emitting diodes (w -LEDs), herein, we report Li2MgTi3O8:Eu3+ as red phosphors that are low-cost eco-materials synthesized by solid-state reaction method. XRD patterns confirm the crystallinity and phase purity of the as-prepared phosphors with the successful incorporation of Eu3+ ions. FTIR, FE-SEM and TEM were used to understand the functional groups and morphology of prepared samples respectively. The band gap energy calculated from DRS showed Burstein–Moss effect. Under 398 nm excitation, intense red emission was recorded at 615 nm and lifetime values were in microsecond range. The prepared phosphor possesses quantum efficiency of 31.74%, good thermal stability with an activation energy of 0.254 eV and exhibit warm red emission with 100% color purity. Therefore, the obtained results suggests that the prepared Li2MgTi3O8:Eu3+ phosphors can be considered as an appropriate candidate for the red component in w- LEDs.

Shallow defects and variable photoluminescence decay times up to 280 µs in triple-cation perovskites.

Quantifying recombination in halide perovskites is a crucial prerequisite to control and improve the performance of perovskite-based solar cells. While both steady-state and transient photoluminescence are frequently used to assess recombination in perovskite absorbers, quantitative analyses within a consistent model are seldom reported. We use transient photoluminescence measurements with a large dynamic range of more than ten orders of magnitude on triple-cation perovskite films showing long-lived photoluminescence transients featuring continuously changing decay times that range from tens of nanoseconds to hundreds of microseconds. We quantitatively explain both the transient and steady-state photoluminescence with the presence of a high density of shallow defects and consequent high rates of charge carrier trapping, thereby showing that deep defects do not affect the recombination dynamics. The complex carrier kinetics caused by emission and recombination processes via shallow defects imply that the reporting of only single lifetime values, as is routinely done in the literature, is meaningless for such materials. We show that the features indicative for shallow defects seen in the bare films remain dominant in finished devices and are therefore also crucial to understanding the performance of perovskite solar cells.

Evaluating Riboglow-FLIM probes for RNA sensing.

We recently developed Riboglow-FLIM, where we genetically tag and track RNA molecules in live cells through measuring the fluorescence lifetime of a small molecule probe that binds the RNA tag. Here, we systematically and quantitatively evaluated key elements of Riboglow-FLIM that may serve as the foundation for Riboglow-FLIM applications and further tool development efforts. Our investigation focused on measuring changes in fluorescence lifetime of representative Riboglow-FLIM probes with different linkers and fluorophores in different environments. In vitro measurements revealed distinct lifetime differences among the probe variants as a result of different linker designs and fluorophore selections. To expand on the platform's versatility, probes in a wide variety of mammalian cell types were examined using fluorescence lifetime imaging microscopy (FLIM), and possible effects on cell physiology were evaluated by metabolomics. The results demonstrated that variations in lifetime were dependent on both probe and cell type. Interestingly, distinct differences in lifetime values were observed between cell lines, while no overall change in cell health was measured. These findings underscore the importance of probe selection and cellular environment when employing Riboglow-FLIM for RNA detection, serving as a foundation for future tool development and applications across diverse fields and biological systems.

A terpyridyl-imidazole based europium tris-(β-diketonate) complex as an efficient molecular luminescent thermometer and single component white light emitter via synergy in energy transfer between ligands and Eu3.

The thermosensing and thermochromic behavior of one of our recently reported terpyridyl-imidazole based ternary europium tris-(β-diketonate) complexes of the composition [Eu(tta)3(tpy-HImzphen)] (tta = 2-thenoyltrifluoroacetone and tpy-HImzphen = 2-(4-[2,2':6',2''] terpyridin-4'-yl-phenyl)-1H-phenanthro[9,10-d]imidazole) has been thoroughly investigated in this work. The said Eu(III) complex exhibits magnificent thermosensing as well as thermochromic properties and can be recommended as an excellent temperature sensor in a wide temperature domain of 273-343 K in terms of both emission intensity ratio (Sm = 5.78% K-1 at Tm = 343 K, δT = 0.012 K) and lifetime values (Sm = 3.36% K-1 at Tm = 333 K, δT = 0.009 K) or even in terms of its emitting color (red at 268 K, violet at 303 K, and blue at 343 K). Additionally, it displays remarkable solvent-induced luminescence behavior by displaying various emitting colors instead of its sole characteristic red emission upon varying the nature of the solvent. Finally, amalgamating these two features, we are able to attain white light emission (Commission Internationale de l'Eclairage coordinates: x = 0.34, y = 0.38) at 283 K from a single component. A plausible energy transfer mechanism has also been proposed in light of the existence of the ligand-to-metal charge transfer (LMCT) state as the quencher.

Convective condensation of R449a inside a smooth tube

The HVAC sector has started the phase-out of refrigerants characterized by high values of global warming potential and atmospheric lifetime. Drop-in replacement requires that the new, environmentally safe fluids also show comparable heat transfer performances. This work addresses R449a, a low GWP zeotropic mixture (components: R32, R125, R1234yf, R134a, mass fractions: 24.3%, 24.7%, 25.3%, 25.7%, respectively), suitable to replace both R404A and R507A. Experiments were carried out on condensation in horizontal smooth tubes (outer diameter: 9.52 mm, thickness: 0.3 mm). The range of operating conditions meets the standard for HVAC devices (operating pressure: 14.46 bar, bubble temperature: 30°C, temperature glide: approximately 5 K refrigerant mass flux ranging from 136 to 202 kg m−2 s−1, quality change -0.8 and -0.2, mean quality ranging from 0.2 to 0.8). The test section is the inner pipe in a tube-in-tube counter-flow heat exchanger, where the refrigerant is cooled by a demineralized water stream in the annulus. Both the pressure drop and the heat transfer coefficient were measured across a length of 1.3 m and 1.1 m, respectively.

Оценка радиационных рисков на индивидуальном уровне при многократном прохождении компьютерной томографии на современных компьютерных томографах

Technological developments, as well as software upgrades to existing computerized tomography (CT) scanners, require a continuous review of the methods for estimating radiation risk from CT procedures. According to the International Commission on Radiological Protection (ICRP), such assessments should be based on absorbed doses in organs and tissues exposed to radiation. This work is devoted to the study of the influence of various characteristics of the CT (manufacturer, type of scanner, etc.) on the evaluation of radiation risks on the example of multiple exposures in standard CT procedures. As an example, the value of lifetime attribute risk (LAR) and lifetime attributable risk fraction (LARF) for 5 CT scans during the life of a woman aged 20, 25, 30, 45 and 50 years is estimated. The lifetime attributable risk of possible cancer induction was estimated according to the ICRP mathematical model (Publication 103) and using the medical and demographic characteristics of the Russian population, as well as scan protocol data for typical CT scanners of selected models. The results were obtained with the use of old and updated conversion factors for the DLP (Dose Length Product – a measure of the absorbed radiation dose for the whole CT examination) parameter to organ doses from a particular procedure. The lifetime attributable risk of possible cancer induction calculated using organ doses derived from old conversion factors was compared with the risk calculated with data for modern CT scanners with updated conversion factors. The LAR was evaluated over time for one CT examination, two, three, four and five different procedures during the patient's lifetime. It was found that to date such factor as software updates in the field of optimisation of scanning protocols or the CT scanner manufacturer still do not has a significant impact on the radiation risks associated with specific diagnostic procedures. The methods developed by the authors for calculating absorbed doses and radiation risks can be used in planning CT examinations and optimising patient dose loads on any modern CT scanners.

Energy exchange between Nd3+ and Er3+ centers within molecular complexes.

Developing controlled and reproducible molecular assemblies incorporating lanthanide centers is a crucial step for driving forward up- and down-conversion processes. This challenge calls for the development of strategies to facilitate the efficient in situ segregation of different Ln metal ions into distinct positions within the molecule. The unique family of pure [LnLn'Ln] heterometallic coordination compounds previously developed by us represents an ideal platform for studying the desired Ln-to-Ln' energy transfer (ET). In this context, we report here the new pure one-step synthetically produced [ErNdEr] (3) complex, which allows for the first time at the molecular level to study the mechanisms behind Nd-to-Er energy transfer. To further assess the photophysical properties of this complex, the analogous [LuNdLu] (1) and [ErLaEr] (2) complexes have also been prepared and photophysically studied. Efficient sensitization via the two β-diketones employed as main ligands was probed for both Nd3+ and Er3+ ions, resulting in highly resolved emission spectra and sufficiently long excited state lifetimes, which allowed further assessment of the Ln-to-Ln' ET. This intermetallic transfer was first detected by comparing the emission spectra of iso-absorbant solutions and demonstrated by comparing the lifetime values with or without the lanthanide quencher (Er3+), as well as with a deep analysis of the excitation spectrum of the three complexes. Thus, a very unique phenomenon was discovered, consisting of a mutual Nd-to-Er and Er-to-Nd ET with no net increase of brightness by any metal; while Nd3+ transfers the energy received from the antenna to Er3+, the sensitization of the latter results in back-transfer to Nd3+ into a non-emissive, thus silent, state.

Three derivatives of phenacyldiphenylphosphine oxide: influence of aromatic and alkyl substituents on the luminescence sensitization of four Ln(NO3)3 salts.

A series of four β-carbonylphosphine oxide compounds have been synthesized, and their complexes with the nitrate salts of Sm3+, Eu3+, Tb3+ and Dy3+ have been characterized in solution and in the solid state. Analysis of the complexes using IR and NMR suggests that metal-ligand binding occurs mainly through the phosphine oxide group of the ligand, with some involvement of the carbonyl group. All 16 complexes luminesce in solutions of acetonitrile, albeit with varying degrees of intensity. The highest quantum yield values obtained for this series are those where the ligand contains an aryl carbonyl group paired with an electron rich phosphine oxide group (29.8 and 11% for the Tb3+ and Eu3+ complexes, respectively). In contrast, the longest emission lifetime values were found for complexes where the ligand contains a bulky substituent on the carbonyl group paired with an electron rich phosphine oxide (1.86, 1.402, 0.045 ms for the Tb3+, Eu3+ and Sm3+ complexes, respectively).

Heteroleptic samarium complexes with high quantum yields for temperature sensing applications.

Two new crystallographically characterized samarium complexes, [Sm(fod)3(L1)] (1) and [Sm(fod)3(L2)] (2) {L1 = 4,7-diphenyl-1,10-phenanthroline (bath), L2 = 2,2':6',2''-terpyridine and fod = anion of 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione (Hfod)}, were synthesized and thoroughly characterized. Single-crystal (SC) analysis shows that complex 1 is an eight-coordinate structure with a distorted square antiprism geometry (D4d), whereas complex 2 possesses a nine-coordinate structure with distorted muffin geometry (Cs). The NMR results are in line with SC-XRD analysis, which further validate that the complexes remain intact in solutions. The photophysical characteristics of the complexes were studied in both visible and near infra-red (NIR) regions. The PLQY values of the present complexes were found to be higher than those reported in the literature except for a tetrakis Sm complex. This result indicates that both the ligands act as effective antennas for the present systems. A comparison of PLQY and emission lifetime values within the present complexes (in solid state) reveals that energy transfer from terpy to Sm3+ is more effective than that from the bath ligand. Various color parameters of the complexes were calculated, and the determined CCT values suggest that the complexes may be used as warm light sources. The determined band gap values for the complexes are in the range of those for semiconductors, which suggest the application of present systems in the field of optoelectronics. The curve between the emission intensity and temperature for complex 1 shows a perfect linearity (χ2 = 0.99), which suggests that this complex can have potential application as a temperature sensor in the range 60-350 K.

Develop Machine Learning Models to Predict Customer Lifetime Value for Banking Customers, Helping Banks Optimize Services

The machine learning algorithms are useful in obtaining suitable data related to customer lifetime value for the banking professionals. The banking officials utilise the Customer lifetime value for fostering suitable business strategies to enhance customer satisfaction in this competitive market. This present study include knowledge regarding machine learning model inclusion to predict customer lifetime values in taking services as well as analysing customer motivation for a banking sector. Inclusion of ML is also effective to handle customer insight in managing business profitability in managing overall business operational activity maintenance. This research has summarised the importance of machine learning model in predicting CLV to Mint and business performance of banks.

SYNTHESIS AND STUDY ON THE PROPERTIES OF CAMOO4:EU3+ CO-DOPEDTB3+ MATERIALS TO ENHANCED RED PHOTOLUMINESCENCE

Ca0.99-yTb0.01MoO4:yEu3+nanophosphors weresuccessfullysynthesizedbyhydrothermal method. All the samples can be excited by 395nm wavelengths for generation of red color emission. Enhancement in 5D0→7 F2 (616 nm) emission (f–f transition) of Eu3+ionis observed when Tb3+ionis co–doped in CaMoO4:Eu3+. This is due to the efficient energy transfer from Tb3+ to Eu3+ ions. Introduction of Tb3+ in the system does not lead to the change of emission wavelength of Eu3+. However, Tb3+and Eu3+co–doped in the system induces a shift in Mo-O charge transfer band absorption from 262nm to (413–431 nm). This may be due to the increase in electronegativity between Mo and O bond in the presence of Eu3+andTb3+leading to change in crystal field environment of Mo6+ in MoO4 2−. At the optimal concentration of Eu3+, an enhancement in emission by a factor of ∼5.6 in the respective excitation at 616nm ( 5D0→7 F2) is observed. The chromaticity coordinates (CIE) of all Ca0.99-yTb0.01MoO4:yEu3+ nanophosphors are in the red region. The luminescence lifetime values are0.812 ms to 1.20 ms. The energy transfer is observed to occur mainly via dipole–dipole interactions.

Bismuth-doped carbon quantum dots as an effective fluorescent probe for metronidazole detection through inner filter effect, cytotoxicity studies, and bioimaging in Zebrafish

Herein we report that Walnut Shell-derived bismuth-doped Carbon Quantum Dots (Bi-CQDs) in rice morphology with an average size of 3–4 nm were used for the highly selective nanomolar (nM) detection of metronidazole (MNZ) through the inner filter effect (IFE). The excitation-dependent Bi-CQDs show high selectivity, sensitivity, and fluorescence detection on different pH (1 → 13) with a limit of detection (LoD) of 15.72 nM (R2 = 0.99092). The fluorescence quenching mechanism was evaluated by the interaction of Bi-CQSs with various MNZ concentrations (200 nM–2 μM), with binding constant as Ka = 1.081 × 10−3 M−1, increase in fluorescence lifetime values (5.60 → 5.88 ns). The interference studies, the effect of pH, the effect of time on MNZ detection, and the stability of the Bi-CQD•MNZ complex were also investigated. Further, in vitro bioimaging of Zebra fish and cytotoxicity studies were also conducted. Fluorescence imaging of Bi-CWDS in Zebra fishes distinguishes the morphology changes and embryogenesis. These results suggest that the developed sensor is highly biocompatible for fluorescence sensing and biological applications.

Energy and economic analysis of an ocean thermal energy conversion plant for Bangladesh: A case study

Bangladesh's surging power demand, especially in coastal regions and nearby islands, necessitates a shift towards sustainable energy sources to meet Sustainable Development Goal 7 (SDG-7) objectives. This research attempts to visualize the ocean thermal energy reserves of the Bay of Bengal, with an extended focus on the marine borders of Bangladesh using advanced data analytics. Extensive data used is from a hybrid ocean coordinate model, Hybrid Coordinate Ocean Model and Navy Coupled Ocean Data Assimilation (HYCOM + NCODA) at 1/12° resolution, which has proven to be sophisticated and precise in providing oceanic information. Analyzing the data shows that geographically Bangladesh is feasible for Ocean Thermal Energy Conversion (OTEC) plants. A model plant is implemented at the potential location, and a Machine Learning (ML) model is trained to forecast temperature values for the future lifetime of the plant. ML forecasted results show the annual average power generated varies between 103.8 and 105.8 MW throughout the plant's life. However, a slight downward trend in generated power is observed, possibly due to climate change. The Levelized Cost of Electricity (LCOE) is calculated at 0.164 USD/kW, with an 11-year payback period. Notably, the plant registers zero Greenhouse Gas (GHG) emissions, aligning with Bangladesh's SDG-13 targets.

Subsurface zone detected in pure nickel by positron annihilation; Hall-Patch effect notification

A dry sliding test and sequential etching technique, combined with positron lifetime measurements on pure nickel, revealed an area of damage below the worn surface extending to a depth of hundreds of micrometers. Some correlation was found between the value of the mean positron lifetime measured directly on the worn surface and the coefficient of friction. The obtained dependency rather confirms the normal Hall-Patch regime. There was no correlation with the specific wear rate.

Recognition of human telomeric G-quadruplex DNA by 1,5-disubstituted diethyl-amido anthraquinone derivative in different ion environments causing thermal stabilization and apoptosis

Ligand binding to G-quadruplex (G4) structures at human telomeric DNA ends promotes thermal stabilization, disrupting the interaction of the telomerase enzyme, which is found active in 80–85% of cancers and serves as a molecular marker. Anthraquinone compounds are well-known G-quadruplex (G4) binders that inhibit telomerase and induce apoptosis in cancer cells. Our current investigation is based on 1,5-bis[3-(diethylamino)propionamido]anthracene-9,10-dione, a derivative of anthraquinone and its binding characterization with two different human telomeric DNA structures, wHTel26 and HTel22, in the effect of K+ and Na+ by using an array of biophysical, calorimetry, molecular docking and cell viability assay techniques. Binding constants (K b) in the range of ∼105–107 M−1 and stoichiometries of 1:1, 2:1 & 4:1 were obtained from the absorbance, fluorescence, and circular dichroism study. Remarkable hypochromism (55, 97%) and ∼17 nm shift in absorbance, fluorescence quenching (95, 97%), the unaltered value of fluorescence lifetime, restoration of Circular Dichroism bands, absence of ICD band, indicated the external groove binding/binding somewhere at loops. This is also evident in molecular docking results, the ligand binds to groove forming base (G4, G5, G24, T25) and in the vicinity to TTA loop (G14, G15, T17) bases of wHTel26 and HTel22, respectively. Thermal stabilization induced by ligand was found greater in Na+ ion (27.5 °C) than (19.1 °C) in K+ ion. Ligand caused cell toxicity in MCF-7 cancer cell lines with an IC50 value of ∼8.4 µM. The above findings suggest the ligand, 1,5-bis[3-(diethylamino)propionamido]anthracene-9,10-dione could be a potent anticancer drug candidate and has great therapeutic implications. Binding of disubstituted amido anthraquinone derivative, 1,5-bis[3-(diethylamino)propionamido]anthracene-9,10-dione to human telomere HTel22 antiparallel conformation induced thermal stabilization. Communicated by Ramaswamy H. Sarma

Modulation of excimer formation and photostability of avobenzone inside the nanocavities of cyclodextrins

Avobenzone (AVZ), a UVA filter, is extensively used in sunscreen lotion and protects the skin from harmful UVA radiation. Despite their importance in sunscreen formulation, less attention has been given to its light induced excited state properties. Herein, we have explored the photophysical properties of AVZ in aqueous solutions and cyclodextrins (CDs) complexes by employing steady-state, time-resolved fluorescence, and molecular modelling tools followed by photostability analysis. AVZ exhibits dual emission from monomer and excimer forms in aqueous solutions. Spectroscopic studies revealed that AVZ forms multiple inclusion complexes with β-CD and γ-CD depending upon the host’s cavity size. These versatile host–guest complexes resulted in the modulation of the excimer formation of AVZ. The presence of α-CD and β-CD complexes with AVZ inhibited the excimer forms. In contrast, γ-CD facilitated excimer formation because its larger cavity could encapsulate the AVZ dimer. Stoichiometry and association constants for multiple host–guest complexes were determined using Benesi-Hildebrand (BH) plot. Job’s plot was used to confirm the stoichiometry of complexes. Time correlated single photon counting (TCSPC) technique was used to depict the excited state lifetime values of AVZ:CD inclusion complexes. Furthermore, these inclusion complexes were characterized by Fourier transform-infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Molecular docking followed by semiempirical calculations confirm the experimental results on stoichiometries and binding constants of host–guest complexes. UV light-induced absorption kinetics revealed that the photostability of AVZ inside the β-CD cavity is much better than other inclusion complexes of CDs. Overall, the present study helps us in further understanding of excited state behavior of AVZ inside hydrophobic nanocavities.

Excited state dynamics of a double ESIPT unit comprising fluorophore

A comprehensive experimental and computational analysis on the photophysical characteristics of a double ESIPT unit based fluorescent molecule, 2,2′-(1,4-phenylenebis(1H-benzo[d]imidazole-1,2-diyl))diphenol (PBIDP), was carried out. Photoluminescence spectra and lifetime decays have been measured in various polar and nonpolar solvents to explore the fluorescence properties. Furthermore, time-resolved area normalized emission spectra are exploited to identify the different conformers to the unsymmetrical keto emission band correlating with their lifetime values. To corroborate the experimental observations, computations have been enacted by calculating the relative energy, excitation and emission energies of different conformers. Especially, the simulation facilitates to trace the reason behind the triple emissions, uncovering the proton transfer dynamics in the double ESIPT based PBIDP system. Additionally, to understand the ESIPT mechanism in the fluorophore, the potential energy curve and transition state in the ground, and excited state were calculated.

Novel Lanthanide Complexes Synthesized from 3-Dimethylamino Benzoic Acid and 5,5'-Dimethyl-2,2' Bipyridine Ligand: Crystal Structure, Thermodynamics, and Fluorescence Properties.

Two isostructural lanthanide complexes were synthesized by solvent evaporation with 3-dimethylaminobenzoic acid and 5,5'-dimethyl-2,2'-bipyridine as ligands. The general formula of the structure is a [Ln(3-N,N-DMBA)3(5,5'-DM-2,2'-bipy)]2·2(3-N,N-DMHBA), Ln = (Gd(1), Tb(2)), 3-N,N-DMBA = 3-Dimethylamino benzoate, 5,5'-DM-2,2'-bipy = 5,5'-dimethyl-2,2' bipyridine. Both complexes exhibited dimeric structures based on X-ray diffraction analysis. At the same time, infrared spectroscopy and Raman spectroscopy were used to measure the spectra of the complex. A thermogravimetric infrared spectroscopy experiment was performed to investigate the thermal stability and decomposition mechanism of the complexes. Measurements of the low-temperature heat capacity of the complexes were obtained within the temperature range of 1.9 to 300 K. The thermodynamic function was calculated by heat capacity fitting. In addition, the fluorescence spectra of complex 2 were studied and the fluorescence lifetime values were determined, and the energy transfer mechanism of complex 2 was elucidated.