Multi spectroscopic and computational investigations on the electronic structure of oxyclozanide

The present work contributes to a combined theoretical and experimental investigation on oxyclozanide. The experimental vibrational spectra were characterized by Fourier transform infrared (4000-400 cm^?1), Fourier transform Raman (4000-400 cm^?1), ¹H and ¹³C NMR were recorded in Deuterated methanol, UV–Vis (200–400 nm) techniques and theoretical optimized molecular geometry, harmonic vibrational spectra, magnetic spectra, and electronic spectra was calculated by Density Functional Theory (DFT) employed with B3LYP/6-311++G(d,p) basis set and compared with experimental data. The highest occupied molecular orbital - lowest unoccupied molecular orbital (HOMO-LUMO) energy was also calculated for the titled compound. The intermolecular interactions have been addressed through Hirshfeld surface analysis. In addition, Natural bond orbital (NBO) analyses of the title compound were performed to evaluate the suitable reactivity site and chemical stabilization behavior, Mulliken atomic charge distribution, and molecular electrostatic potential energy surfaces, were calculated to get a better insight into the structure of oxyclozanide. The experimental and theoretical findings suggest an excellent correlation to confirm the structure of oxyclozanide.     

Spectral analysis of acetylcholine halides by density functional theory calculations

The optimized molecular structures, vibrational frequencies and ¹H and ¹³C NMR chemical shifts of acetylcholine halides (F, Cl, and Br) have been investigated using density functional theory (B3LYP) method with 6-311G(d) basis set. The comparison of their experimental and calculated IR, R and NMR spectra of the compounds has indicated that the spectra of three optimized minimum energy conformers can simultaneously exist in one experimental spectrum. Thus, it was concluded that the compounds simultaneously exist in three conformations in the ground state. The calculated optimized geometric parameters (bond lengths and bond angles), vibrational frequencies and NMR chemical shifts for the minimum energy conformers were seen to be in a good agreement with the corresponding experimental data. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program.     

FT-IR,FT-Raman,NMR spectra and DFT calculations on 4-chloro-N-methylaniline

In this work, the vibrational spectral analysis was carried out by using FT-IR and FT-Raman spectroscopy in the range 400–4000 and 50–3500 cm^?1 respectively, for the title molecule. The structural and spectroscopic data of the molecule in the ground state were calculated by using density functional method using 6-311++G(d,p) basis set. The vibrational frequencies were calculated and scaled values were compared with experimental FT-IR and FT-Raman spectra. The observed and calculated frequencies are found to be in good agreement. The complete assignments of all the vibrational mode were performed on the basis of the total energy distributions (TED). ¹³C and ¹H NMR chemical shifts results were given and are in agreement with the corresponding experimental values. The theoretically constructed FT-IR and FT-Raman spectra exactly coincides with experimental one.     

Quantum‐chemical,IR, NMR,and X‐ray diffraction studies on 2‐(4‐chlorophenyl)‐1‐methyl‐ 1H‐benzo[d]imidazole

The title molecule, 2‐(4‐chlorophenyl)‐1‐methyl‐1H‐benzo[d]imidazole (C₁₄H₁₁ClN₂), was prepared and characterized by ¹H NMR, ¹³C NMR, IR, and single‐crystal X‐ray diffraction. The molecular geometry, vibrational frequencies, and gauge including atomic orbital (GIAO) ¹H and ¹³C NMR chemical shift values of the title compound in the ground state have been calculated by using the Hartree‐Fock (HF) and density functional theory (DFT/B3LYP) method with 6‐31G(d) basis sets, and compared with the experimental data. The calculated results show that the optimized geometries can well reproduce the crystal structural parameters, and the theoretical vibrational frequencies and GIAO ¹H and ¹³C NMR chemical shifts show good agreement with experimental values. The energetic behavior of the title compound in solvent media has been examined using B3LYP method with the 6‐31G(d) basis set by applying the Onsager and the polarizable continuum model (PCM). Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis, and nonlinear optical (NLO) properties of the title compound were investigated by theoretical calculations. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Molecular structure,vibrational spectra,first order hyper polarizability,NBO and HOMO–LUMO analysis of 4-amino-3(4-chlorophenyl) butanoic acid

The Fourier transform infrared (FT-IR) and Fourier transform Raman (FTR) spectra of 4-amino-3(4-chlorophenyl) butanoic acid were recorded in the regions 4000–400 cm⁻¹ and 4000–100 cm⁻¹, respectively, in the solid phase. Molecular electronic energy, geometrical structure, harmonic vibrational spectra, infrared intensities and Raman scattering activities, highest occupied molecular orbital, lowest unoccupied molecular orbital energy, energy gaps and thermodynamical properties such as zero-point vibrational energies, rotational constants, entropies and dipole moment were computed at the Hartree–Fock/6-31G(d,p) and three parameter hybrid functional Lee–Yang–Parr/6-31G(d,p) levels of theory. The vibrational studies were interpreted in terms of potential energy distribution (PED). The results were compared with experimental values with the help of scaling procedures. Most of the modes have wave numbers in the expected range and are in good agreement with computed values. The first order hyperpolarizability (β_total) of this molecular system and related properties (β, μ, 〈α〉 and Δα) are calculated using HF/6-31G(d,p) and B3LYP/6-31G(d,p) methods based on the finite-field approach. Stability of the molecule arising from hyperconjugative interactions, charge delocalization and intramolecular hydrogen bond-like weak interaction has been analyzed using natural bond orbital (NBO) analysis by using B3LYP/6-31G(d,p) method. The results show that electron density (ED) in the σ1 and π1 antibonding orbitals and second-order delocalization energies E⁽²⁾ confirm the occurrence of intramolecular charge transfer (ICT) within the molecule.     

FT-IR, FT-Raman, vibrational assignments, and density functional studies of 1,2,4-triazole-3-carboxylic acid, and its tautomers, dimers

The molecular geometry, relative energy, and vibrational properties (harmonic wavenumbers, total energy distributions) of several plausible tautomers and homodimers of 1,2,4-triazole-3-carboxylic acid (TCA) molecule were analyzed by applying the density functional theory (DFT), with the B3LYP functional and the 6-311++G(d,p) basis set. FT-IR and FT-Raman spectra of the biomolecule TCA were recorded in the regions 4000–100 cm⁻¹ and 3500–100 cm⁻¹, respectively. The calculated vibrational wavenumbers were compared with IR and Raman experimental data. The atomic charges and the dimer forms of the most stable tautomer were also discussed.     

Computational description of quantum chemical calculations and pharmacological studies of the synthesized chalcone derivative: A promising NLO material

The intended chalcone, (E)-1-(4-aminophenyl)-3-(4-ethoxyphenyl)-prop-2-en-1-one (4A3EP), was synthesized in an alkaline medium by the Claisen–Schmidt condensation reaction of 4-aminoacetophenone with 4-ethoxybenzaldehyde. Spectroscopic analytical techniques such as UV–visible, FT-IR, FT-RAMAN, ¹H NMR, and ¹³C NMR investigations were used to analyze the molecular structure of the title molecule. The optimized molecular structure of the chalcone in gas phase vibrational frequencies and associated vibrational assignments were theoretically studied and compared with experimental results using the B3LYP/6–311++G techniques. All the experimental results were found to be in line with the theoretical values. The non linear optical activity of the title compound was proved from the hyperpolarizability calculations. In addition, E_HOMO (?5.9038 eV), E_LUMO (?2.2833 eV), energy gap (3.6205 eV) and electrophilicity index (4.628) were calculated to explore the reactivity, stability and bio activity of the title compound. The molecular electrostatic potential map was generated in order to spot the electrophilic and nucleophilic sites in the title compound. Natural bond orbital analysis was investigated in order to forecast the stability and charge transfer tendency of a title molecule. FUKUI FUNCTIONS were also calculated using DFT. Its anti-inflammatory, anti-diabetic, and anti-oxidant activities were also investigated. A molecular docking model was used to study the ligand-protein binding interactions of a synthetic chalcone derivative with the main protease of SARS-CoV-2 (the PDB code is 6yb7).     

Synthesis, molecular conformation, vibrational and electronic transition, isometric chemical shift, polarizability and hyperpolarizability analysis of 3-(4-methoxy-phenyl)-2-(4-nitro-phenyl)-acrylonitrile: a combined experimental and theoretical analysis

This work presents the synthesis and characterization of a novel compound, 3-(4-Methoxy-phenyl)-2-(4-nitro-phenyl)-acrylonitrile (abbreviated as 3-(4MP)-2-(4-NP)-AN, C₁₆H₁₂N₂O₃). The spectroscopic properties of the compound were examined by FT-IR, UV–vis and NMR (¹H and ¹³C) techniques. FT-IR spectrum in solid state was observed in the region 4000–400 cm⁻¹. The UV–vis absorption spectrum of the compound which dissolved in chloroform was recorded in the range of 200–800 nm. The ¹H and ¹³C NMR spectra were recorded in CDCl₃ solution. To determine lowest-energy molecular conformation of the title molecule, the selected torsion angle is varied every 10° and molecular energy profile is calculated from 0° to 360°. The structural and spectroscopic data of the molecule in the ground state were calculated using density functional theory (DFT) employing B3LYP/6-31G(d,p) basis set. The dipole moment, linear polarizability and first hyperpolarizability values were also computed using the same basis set. A study on the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The HOMO and LUMO analysis were used to elucidate information regarding charge transfer within the molecule. The vibrational wavenumbers were calculated and scaled values were compared with experimental FT-IR spectrum. The complete assignments were performed on the basis of the experimental results and total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. Isotropic chemical shifts were calculated using the gauge-invariant atomic orbital (GIAO) method. Comparison of the calculated frequencies, NMR chemical shifts, absorption wavelengths with the experimental values revealed that DFT and TD-DFT method produce good results. The linear polarizabilities and first hyperpolarizabilities of the studied molecule indicate that the title compound can be used as a good nonlinear optical material. The thermodynamic properties of the studied compound at different temperatures were calculated, revealing the correlations between standard heat capacity, standard entropy, standard enthalpy changes and temperatures.     

Synthesis,molecular conformation,vibrational, electronic transition,and chemical shift assignments of 4-(thiophene-3-ylmethoxy)phthalonitrile: a combined experimental and theoretical analysis

This work presents the synthesis and characterization of a novel compound, 4-(thiophene-3-ylmethoxy)phthalonitrile (TMP). The spectroscopic properties of the compound were examined by FT-IR, FT-Raman, NMR, and UV techniques. FT-IR and FT-Raman spectra in solid state were observed in the region 4000–400 cm⁻¹ and 3500–50 cm⁻¹, respectively. The ¹H and ¹³C NMR spectra were recorded in CDCl₃ solution. The UV absorption spectrum of the compound that dissolved in THF was recorded in the range of 200–800 nm. The structural and spectroscopic data of the molecule in the ground state were calculated using density functional theory (DFT) employing B3LYP exchange correlation and the 6-311++G(d,p) basis set. The vibrational wavenumbers were calculated and scaled values were compared with experimental FT-IR and FT-Raman spectra. The complete assignments were performed on the basis of the experimental results and total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. Isotropic chemical shifts (¹³C NMR and ¹H NMR) were calculated using the gauge-invariant atomic orbital (GIAO) method. A study on the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The HOMO and LUMO analyses have been used to elucidate information regarding charge transfer within the molecule. Comparison of the calculated frequencies, NMR chemical shifts, absorption wavelengths with the experimental values revealed that DFT method produces good results.     

Ab initio and semiempirical computational studies on 1‐{(2E)‐2‐[(aminocarbonothioyl)hydrazono]‐2‐(3‐mesityl‐3‐methylcyclobutyl)ethyl}‐pyrrolidine‐2,5‐dione

The molecular geometry, vibrational frequencies, and gauge including atomic orbital (GIAO) ¹H‐ and ¹³C NMR chemical shift values of the title compound in the ground state have been calculated using the Hartree‐Fock (HF) and density functional theory (DFT) methods with 6‐31G(d) basis sets, and compared with the experimental data. The calculated results show that the optimized geometries can well reproduce the crystal structural parameters and the theoretical vibrational frequencies, and ¹H‐ and ¹³C NMR chemical shift values show good agreement with experimental data. To determine conformational flexibility, the molecular energy profile of the title compound was obtained by semiempirical (AM1) calculations with respect to the selected torsion angle, which was varied from ?180° to +180° in steps of 10°. The energetic behavior of the title compound in solvent media was examined using the B3LYP method with the 6‐31G(d) basis set by applying the Onsager and the polarizable continuum model (PCM). The results obtained with these methods reveal that the PCM method provided more stable structure than Qnsager's method. By using TD‐DFT method, electronic absorption spectra of the title compound have been predicted and a good agreement with the TD‐DFT method and the experimental one is determined. The predicted nonlinear optical properties of the title compound are much greater than ones of urea. In addition, the molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis, NBO analysis and thermodynamic properties of the title compound were investigated using theoretical calculations. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012     

Molecular structure, vibrational spectroscopic, first hyperpolarizability, NBO and HOMO, LUMO studies of P-Iodobenzene sulfonyl chloride

In this work, the experimental and theoretical vibrational spectra of P-Iodobenzene sulfonyl chloride (P-IBSC) were studied. P-IBSC and its derivatives present in many biologically active compounds. Because of their spectroscopic properties and chemical significance in particular, sulfonyl chloride and its derivatives have been studied extensively by spectroscopic (FTIR and FT-Raman spectra) and theoretical methods. The infrared spectra of these compounds were recorded in condensed states, while the Raman spectra were measured without polarization using both parallel and perpendicular polarizations of scattered light. The molecular geometry, highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), first order hyperpolarizability and thermodynamic properties of P-IBSC have been computed with the help of density functional theory (B3LYP) and ab initio (HF) methods with the LanL2DZ basis set. The HOMO and LUMO energy gap explains the charge transfer interactions taking place within the molecule. NBO study explains charge delocalization of the molecule. The contributions of the different modes to each wave number were determined using potential energy distributions (PEDs). The experimental and calculated results were consistent with each other.     

Theoretical and experimental study on metal(II) halide complexes of 1,3-bis(4-pyridyl)propane

We report the results of detailed experimental and theoretical studies on the molecular structure and vibrational spectra of metal(II) halide complexes of 1,3-bis(4-pyridyl)propane [M(N₂C₁₃H₁₄)X₂, where M represents Zn or Hg, and X represents Cl, Br, or I]. The FT–infrared spectra (FT-IR) and FT-Raman spectra of the metal complexes of the 1,3-bis(4-pyridyl)propane molecule in the powder form were recorded between the 400–4000 and 5–3500 cm^?1 regions, respectively. The molecular geometry and vibrational frequencies of the metal complexes of 1,3-bis(4-pyridyl)propane in the ground state were calculated using density functional theory (B3LYP functional) with LANL2DZ and SDD as basis sets. The total energy distributions (TED) among the symmetry coordinates of the normal modes were computed for the low-energy structure of the molecules. Complete vibrational assignments based on the calculated TED values are given.     

DFT computations,vibrational spectra,monomer, dimer,NBO and NMR analyses of antifungal agent: 3,5-Dibromosalicylic acid

The experimental and theoretical study on the structures and vibrations of 3,5-dibromosalicylic acid (DBSA) are presented. The FT-IR and FT-Raman of the title compound have been recorded. The molecular structures, vibrational wavenumbers, infrared intensities, Raman activities were calculated. The energies of DBSA are obtained for all the eight conformers from density functional theory with 6-311++G(d,p) basis set calculations. From the computational results, C1 or C5 forms are identified as the most stable conformers of DBSA. The spectroscopic and theoretical results are compared with the corresponding properties for DBSA monomer and dimer of C1 (or C5) conformer. Intermolecular hydrogen bonds are discussed in dimer structure of the molecule. NBO analysis is useful to understand the intramolecular hyperconjugative interaction between lone pair O9 and C7O8. The calculated HOMO–LUMO energies reveal charge transfer occurs within the molecule. The polarizability, first hyperpolarizability, anisotropy polarizability invariant has been computed using quantum chemical calculations. The isotopic chemical shift computed by ¹H and ¹³C nuclear magnetic resonance (NMR) chemical shifts of the DBSA molecule, calculated using the gauge invariant atomic orbital (GIAO) method, also shows good agreement with experimental observations.     

A comparative spectroscopic,electronic structure and chemical shift investigations of o-Chloronitrobenzene,p-Chloronitrobenzene and m-Chloronitrobenzene

The structural characteristics and substituent effects of o-Chloronitrobenzene, m-Chloronitrobenzene and p-Chloronitrobenzene have been analysed by experimental FTIR, FT-Raman and FT-NMR spectroscopic studies. A detailed quantum chemical calculations have been performed using DFT/B3LYP method with 6-311++G^**, 6-31G^** and cc-pVTZ basis sets. Complete vibrational analyses of the compounds were performed. The temperature dependence of thermodynamic properties has been analysed. The atomic charges and charge delocalisation of the molecule have been performed by natural bond orbital (NBO) analysis. Molecular electrostatic surface potential (MESP), total electron density distribution and frontier molecular orbitals (FMOs) are constructed at B3LYP/6-311++G^** level to understand the electronic properties. The charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential surfaces (ESPs). The electronic properties, HOMO and LUMO energies were measured by time-dependent TD-DFT approach. ¹H and ¹³C NMR spectra were recorded and ¹H and ¹³C nuclear magnetic resonance chemical shifts of the molecule were calculated. The ¹H and ¹³C nuclear magnetic resonance (NMR) chemical shifts of the molecules in chloroform solvent were calculated by using the Gauge-Independent Atomic Orbital (GIAO) method and are found to be in good agreement with experimental values.     

Density functional theory studies on the structure,spectra (FT-IR,FT-Raman,and UV) and first order molecular hyperpolarizability of 2-hydroxy-3-methoxy-N-(2-chloro-benzyl)-benzaldehyde-imine: Comparison to experimental data

The infrared and Raman spectra of 2-hydroxy-3-methoxy-N-(2-chloro-benzyl)-benzaldehyde-imine (HMCBI) have been recorded and analyzed. Density functional calculations at B3LYP/6-311++G(d,p) level were carried out to study the equilibrium geometries and vibrational spectra of HMCBI. The calculations revealed that the optimized geometry closely resembled the experimental XRD data. The calculated vibrational spectra were analyzed on the basis of the potential energy distribution (PED) of each vibrational mode, which allowed us to obtain a quantitative as well as qualitative interpretation of IR and Raman spectra. The ¹H nuclear magnetic resonance (NMR) chemical shifts of the molecule in the ground state were calculated by Gauge independent atomic orbital (GIAO) method. Information about size, shape, charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential surface. Based on optimized ground state geometries, the NBO analysis has been done to study donor–acceptor (bond–antibond) interactions. The TD-DFT method has been used to calculate energies, oscillator strengths of electronic singlet–singlet transitions and the absorption wavelengths. Solvent effects were considered using the polarizable continuum model (PCM). Good consistency is found between the calculated results and experimental data for the electronic absorption. The calculated first hyperpolarizability may be attractive for further studies on non-linear optical properties of materials.     

Spectroscopic investigations (FTIR,UV-VIS,NMR) and DFT calculations on the molecular structure of Nω-Nitro-L-arginine

The spectroscopic properties of N_ω-nitro-l-arginine were investigated by FT-IR, UV-VIS, and ¹H NMR spectra. Geometrical parameters and energies were calculated using the density functional theory (DFT) B3LYP method with the 6-311G basis set. Geometrical optimization of the molecule has been performed, vibrational spectra have been calculated, and fundamental vibrations have been determined from the total energy distribution (TED) of the vibrational modes. The HOMO-LUMO analysis is carried out for various electric fields (0.0–0.025 A^?1). The HOMO-LUMO gap is decreased while increasing the electric field. The calculated quantum chemical parameters are calculated and correlated to the inhibition efficiency, A Mullliken population was also important for determining local reactivity by indicating reactive centers and identifying potential nucleophilic and electrophilic attack sites. Charge transfer occurs inside the compound based on the HOMO LUMO gap. Calculations of DFT were evaluated in their ability to predict inhibition efficiency.     

Ab initio- and density-functional studies of conformational behaviour of N-formylmethionine in gaseous phase

The current work is a study of the conformational space of the non-ionic N-formylmethionine molecule around its seven structurally significant internal backbone torsional angles at B3LYP/6-31++G(d,p) levels of theory in the gaseous phase. The potential energy surface exploration reveals that a total of 432 different conformers would result if all the possible combinations of the internal rotations were to be considered. A set of twelve conformers of the N-formylmethionine molecule are then further analysed in terms of their relative stabilities, theoretically predicted harmonic vibrational frequencies, HOMO-LUMO energy gaps, ESP charges, rotational constants and dipole moments calculated using MP2/6-31++G(d,p) and B3LYP/6-311++G(d,p) levels. The calculated relative energy-range of the conformers at the MP2 level is 11.08 kcal mol^?1 (1 kcal = 4.1868 kJ), whereas the same obtained at the B3LYP level is 10.02 kcal mol^?1. The results of this study provide a good account of the role of four types of intramolecular H-bonds, namely O…H—O, O…H—N, O…H—C and N…H—C, in influencing the energies of the conformers as well as their conformational and vibrational spectroscopic aspects. The relative stability order of the conformers appears to depend on the level of theory used while the vibrational frequencies calculated at the B3LYP level are in better agreement with the experimental values.     

Quantum chemical calculation,topological analysis,biological evaluation and molecular docking of allo-ocimenol against breast cancer

The main aim of this study is to identify the structural stability of allo-ocimenol and its molecular reactivity against breast cancer-associated proteins to confirm its anti-cancer capability using density function theory and molecular docking analysis. The structural optimization was carried out via the DFT/B3LYP technique with a 6-311++G (d,p) basis set. The molecular geometry and vibrational assignments of the Allo-Ocimenol molecule were analyzed through density functional theory (DFT). Through optimized molecular structure, the vibrational frequencies (FT-IR and FT-Raman) were assigned and related with experimentally observed vibrational frequencies and the UV spectrum was computed and experimentally confirmed. The allo-ocimenol's reactive activity was further analyzed through a computed molecular electrostatic potential surface. Utilizing the HOMO-LUMO energies and molecular electrostatic potential energy gap, the reactivity and molecular stability of the allo-ocimenol molecule was calculated. Mulliken and natural population analyses were used to determine the charge distribution across the allo-ocimenol atoms. The natural bond orbitals were used to demonstrate the bioactivity of the titled molecule. RDG evaluation was used to examine the weak interactions of the allo-ocimenol molecule. ELF and LOL analyses were utilized to investigate the topology of the allo-ocimenol molecule. Thermodynamic evaluation has been utilized to acquire values and asses the thermodynamic parameters that reveal the thermal stability of the title molecule. Allo-Ocimenol's anti-microbial activity was assessed through an in-vitro disc diffusion method, and its tumor inhibitory and pharmacokinetic properties were evaluated through an in-silico approach using molecular docking and ADMET investigation. Zones of clearance were seen in anti-microbial analyses at various concentrations, and the breast cancer target protein NAMPT established the greatest binding potential, with a docking value of −7.4 Kcal mol⁻¹.     

FT-IR, FT-Raman and UV spectral investigation; computed frequency estimation analysis and electronic structure calculations on 1-nitronaphthalene

In this work, the vibrational spectral analysis was carried out by using FT-Raman and FT-IR spectroscopy in the range 100-4000cm(-1) and 400-4000cm(-1) respectively, for 1-nitronaphthalene (C(10)H(7)NO(2)) molecule. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and normal coordinate force field calculations based density functional theory (DFT) and ab initio HF methods and different basis sets combination. The complete vibrational assignments of wavenumbers were made on the basis of total energy distribution (TED). The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The scaled B3LYP/6-311++G(d,p) results show the best agreement with the experimental values over the other methods. The energy and oscillator strength calculated by time-dependent density functional theory (TD-DFT) complements with the experimental findings. Thermodynamic properties of the title compound at different temperatures have been calculated. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) were performed.     

三原子反应散射内态角分布的准经典计算

本工作利用分子反应动力学的准经典理论计算了原子与双原子分子三维反应散射产物内态振转角分布, 并得出振动分支比这一重要动态学信息。计算采用了半经验的LEPS形式的解析势能面。初始碰撞参数利用普遍使用的Monte Carlo方法确定。本文给出F+H_2(D_2)→HF(DF)+H(D)反应的计算结果, 并与最新交叉分子束实验进行了广泛的比较, 得到完全一致的规律。