Calculation of rotationally vibrational energy of HDO molecule

The anharmonic constants and the constants of rotation-vibration interaction have been calculated for an asymmetrical non-linear three atomic molecule on the assumption that Pliva's potential function for polyatomic molecules is valid.     

The impact of vibrational wave function on low energy electron vibrational scattering from nitrogen molecule

The vibrational wave function of the target theoretically plays an important role in the calculation of vibrational excitation cross sections. By a careful study of the differential cross sections resulting from different vibrational wave functions we find that cross sections are susceptible to vibrational wave functions. Minor changes in the vibration wave function may cause a significant change in the cross section. Even more surprising is that by selecting a few numbers of potential models(which determine the vibrational wave functions) we can often calculate the differential scattering cross section in much closer agreement with experiment in the framework of body-frame vibrational close-coupling theory, which suggest that an accurate potential energy may play a more important role in scattering than we thought before.     

A role of solvent in vibrational energy relaxation of metalloporphyrins

The formation of a vibrationally excited photoproduct of metalloporphyrins upon (π, π*) excitation and its subsequent vibrational energy relaxation were monitored by picosecond time-resolved resonance Raman spectroscopy. Stokes Raman bands due to a photoproduct of nickel octaethylporphyrin (NiOEP) instantaneously appeared upon the photoexcitation. Their intensities decayed with a time constant of 300 ps, which indicates electronic relaxation from the (d, d) excited state (B_1g) to the ground state (A_1g), being consistent with the results of transient absorption measurements by Holten and coworkers. Anti-Stokes ν₄ and ν₇ bands for vibrationally excited (d, d) state of NiOEP decayed with time constants of 10 and 300 ps. The former is ascribed to vibrational relaxation, while the latter corresponds to the electronic relaxation from the (d, d) excited state to the electronic ground state. While the rise of anti-Stokes ν₄ intensity was instrument-limited, the rise of anti-Stokes ν₇ intensity was delayed by 2.6±0.5 ps, which indicates that intramolecular vibrational energy redistribution has not been completed in subpicosecond time regime. To study a mechanism of intermolecular energy transfer, solvent dependence of the time constants of anti-Stokes kinetics was investigated using various solvents. No significant solvent dependence of the rise and decay constants was observed for NiOEP. For an iron porphyrin, we observed two phases in intermolecular energy transfer. The fast phase was insensitive to solvent and the slow phase depended on solvents. A model of classical thermal diffusion qualitatively reproduced this behavior. For solute-solvent energy transfer process, low-frequency modes of proteins seem to be less important.     

On the study of the vibrational energy levels of Arsine molecule

We compare two formalisms applied to the vibrational modes of the molecule of AsH₃ of C_3v molecular symmetry group. Indeed, the close stretching modes of this molecule may be considered as those of a three-dimensional oscillator whereas the bending modes may be considered either as a one-dimensional oscillator of symmetry A₁ and a two-dimensional oscillator of symmetry E or as an approximate three-dimensional oscillator. So, we have applied the U(p + 1) formalism to the both stretching and bending modes and introduced coupling terms acting on an appropriate coupled vibrational basis through a local mode formalism. We have then compared the result of our fitting with those obtained with the coupling of a local mode formalism adapted to the stretching vibrations with a normal mode formalism for the bending ones. Finally we compare our results with other methods recently proposed in the literature.     

The potential energy function of the nitrous oxide molecule using pure vibrational data

Using a very large and partly new set of vibrational data, a preliminary determination of the potential energy function of the nitrous oxide molecule has been undertaken and the results are presented in this paper. These results are discussed.     

Thermal rotations and relaxation of vibrational energy of excited dye molecules in solution

Measurements of polarization and decay time of fluorescence of dyes in solution as a function of excitation wavelength were performed. The rate of thermal rotational depolarization was found to be independent of vibrational energy excess. To explain the observed influence of excitation wavelength on the emission anisotropy, a change in the magnitude of torsional vibrations, in addition to possible mixing of states, is proposed.     

Calculation of vibrational energy levels of water molecule by summing divergent perturbation theory series

The Rayleigh-Schrödinger perturbation theory is applied to a calculation of vibrational energy levels of the H₂O molecule for isolated states and the states involved in the anharmonic Fermi and Darling-Dennison resonances. It is shown that in spite of the rapid divergence of the perturbation theory series caused by the resonances, the use of the summation methods of Padé, Padé-Borel, and Padé-Hermite and the moments method allows one to obtain quite satisfactory results.     

能谱涨落统计特征稳定性分析

通过引入权重,并用一能级数等于简并谱的无趋向性序列为标准去衡量 简并邻间距谱的趋向性,由此建立分析简并谱涨落统计特征稳定性的MKS无参量试验法;根 据该方法,具体分析、比较了H2O分子低激发态与高激发态振动能谱涨落统计特征,找出 了从低激发态向高激发态过度时涨落统计特征明显改变点。     

可激发气体分子声弛豫过程振动模式能量转移速率计算

研究可激发气体中振动模式能量转移速率和声弛豫过程形成的关系,将单一气体Tanczos弛豫方程理论[J.Chem.Phys.25,439(1956)]扩展应用于混合气体中振动模式的振动-振动(V-V)和振动-平动(V-T)能量转移速率的计算。在室温下CO₂,CH₄,CL₂,N₂和O₂组成的多种混合气体中,振动模式能量转移速率的计算结果表明:对于多个振动模式所形成的声复合弛豫过程,各振动模式的声激发能可由V-V能量转移相互耦合后传递给具有最快V-T转移速率的最低振动频率振动模式,再通过该振动模式的V-T转移退激发形成主弛豫过程。这种选择最快转移路径的声激发量弛豫方式,造成了大多数可激发气体中声弛豫吸收谱的实测数据只存在一个吸收峰的现象。从而提供了一个可通过计算微观振动能量转移速率分析混合气体声弛豫过程形成机理的理论模型。     

Calculation of vibrational energy transition rates in acoustic relaxation processes for excitable gas molecules

To research the correlation between vibrational energy transition rates and acoustic relaxation processes in excitable gases, the vibrational relaxation theory provided by Tanczos [J.Chem. Phys. 25, 439(1956)] is applied to calculate the energy transition rates of VibrationalVibrational(V-V) and Vibrational-Translational(V-T) energy transfer in gas mixtures. The results of calculation for the multi-relaxation processes in various gas mixtures, consisting of carbon dioxide, methane, chlorine, nitrogen, and oxygen at room temperature, demonstrate that the acoustic energy stagnated in every vibrational mode is coupled with each other through V-V energy exchanges. The vibrational excitation energy will relax through the V-T de-excitation path of the lowest mode because of its fastest V-T transition rate, resulting in that only one absorption peak can be measured for most of excitable gas mixtures. Thus, an effective model is provided to analyze how the vibrational energy transition rates affect the characteristics of acoustic relaxation processes and acoustic propagation in excitable gas mixtures.     

NaLi分子的完全振动能谱和离解能的研究

文章使用作者建立的基于微扰理论的代数方法(AM),首次研究了碱金属异核双原子分子NaLi的 、 、 三个电子态的振动光谱常数和振动能谱;使用基于AM的代数能量方法（AEM）研究了这些电子态的离解能。结果表明：根据少数精确的实验振动能级[ ],用AM方法获得了精确的分子振动光谱常数集合,还首次获得了包含所有高振动量子态能级的正确的完全振动能谱{ };用AEM方法获得的分子离解能比由文献发表的振动光谱常数计算得到的离解能值更准确。     

Investigation of vibrational relaxation of excimers

The excimer vibtational relaxation have been studied in the diffusional approximation, and stationary substantially non-equilibrium populations of high vibrational levels have been found. New formulae have been derived for quantum yield of UV lasing. Taking into account the vibrational relaxation the new effect of far-IR radiation amplification in the active media of excimer lasers is predicted.     

Multistability of states of a molecular gas with the V-T relaxation time dependent on the vibrational energy

The possibility of realizing multistability of states under the action of IR radiation on a molecule under conditions of nonlinear absorption of light energy and dependence of the V-T relaxation time on its vibrational energy is shown. A two-wave optically bistable arrangement potentially having a highly contrasting range of states is proposed. The nonlinear dependence of the V-T relaxation time on the vibrational energy is shown to allow the realization of optical bistability based on the absorption of light energy at the frequency of the fundamental vibrational transition.     

Decay of correlations in vibrational relaxation

We investigate the decay of initial vibrational correlations in a dilute gas mixture of diatomic molecules and structureless particles. We use the techniques of Davis and Oppenheim to derive an equation for vibrational relaxation which is suitable for correlated systems. We then use the Landau-Teller transition probabilities and solve for the one-and two-molecule distribution functions and the two-molecule correlation functions. We find that the correlations decay faster than the distribution functions, which agrees with the results of Oppenheim, Shuler,et al. for other systems.     

Surface vibrational studies of organic molecule chemisorption on silicon

We discuss the most interesting results of an extensive research program on the chemisorption properties of organic molecules on semiconductor substrates. Specific systems discussed in detail are benzene, pyridine and thiophene on cleaved Si(111). In particular, we find that the chemisorption of benzene or pyridine on room-temperature substrates leads to the breaking of C-H bonds in the absorbed molecules and to the formation of Si-C bonds.     

NaK分子的完全振动能谱和离解能的研究

使用作者建立的基于微扰理论的代数方法(AM),研究了碱金属异核双原子NaK的 、 两个电子态的振动光谱常数和振动能谱;使用基于AM的代数能量方法（AEM）研究了这些电子态的离解能。结果表明：根据少数精确的实验振动能级[ ],用AM方法获得了精确的分子振动光谱常数集合,还首次获得了包含所有高振动量子态能级的正确的完全振动能谱{ };用AEM方法获得的分子离解能比由文献发表的振动光谱常数计算得到的离解能值更准确。     

NaK分子的完全振动能谱和离解能的研究

使用作者建立的基于微扰理论的代数方法(AM),研究了碱金属异核双原子NaK的 、 两个电子态的振动光谱常数和振动能谱;使用基于AM的代数能量方法（AEM）研究了这些电子态的离解能。结果表明：根据少数精确的实验振动能级[ ],用AM方法获得了精确的分子振动光谱常数集合,还首次获得了包含所有高振动量子态能级的正确的完全振动能谱{ };用AEM方法获得的分子离解能比由文献发表的振动光谱常数计算得到的离解能值更准确。     

Ratio between phase and energy intramolecular vibrational relaxation times of polyatomic anions in solutions of electrolytes

A comparative analysis of intramolecular vibrational relaxation times of polyatomic anions in solutions of electrolytes and vibrational energy relaxation times was performed. Vibrational relaxation times were calculated by analyzing the form of isotropic Raman scattering bands. The conclusion was drawn that the main process responsible for the formation of the isotropic contour of Raman symmetrical stretching vibration bands of anions in solutions of electrolytes was vibrational dephasing. Because of the formation of ion-molecular H-bonds, vibrational dephasing and energy relaxation times decreased substantially differently.