This feature article discusses some selected aspects in the field of vibrational structure calculations based on vibrational self-consistent field, VSCF, and vibrational configuration interaction, VCI, theory. As the quality of such calculations depends strongly on the accuracy of the underlying multidimensional potential energy surface, PES, some techniques will be discussed to establish high-...

to get a mole of a gas, it is necessary to calculate the intermolecular interaction. theseintermolecular interactions can be depicted by drawing the potential energy of a pair molecule inrelation to the distance. the intermolecular potential energy surface in the mixtures of ch4-h2cogases from ab initio calculations has been explored. in ab initio calculations the basis setsuperposition error (...

A linearized approximation to the semiclassical initial value representation ~SC-IVR!, referred to herein as the LSC-IVR, was used by us in a recent paper @J. Chem. Phys. 108, 9726 ~1998!# to calculate reactive flux correlation functions for a model of a chemical reaction on a single potential energy surface. This paper shows how the LSC-IVR—which is much easier to apply than the full SC-IVR be...

Aims. The objective is to obtain the best possible set of rotational (de)-excitation state-to-state and effective rate coefficients for temperatures up to 1500 K. State-to-state rate coefficients are presented among the 20 lowest levels of para-H2O with H2( j2 = 1) and Δ j2 = 0,+2, and among the 10 lowest levels of para-H2O with H2( j2 = 3) and Δ j2 = 0,−2. Methods. Calculations are performed w...

Femtosecond time-resolved velocity map imaging experiments are reported on several vibronic levels of the second absorption band (B-band) of CH3I, including vibrational excitation in the ν2 and ν3 modes of the bound R1(E) Rydberg state. Specific predissociation lifetimes have been determined for the 20 and 3 1 0 vibronic levels from measurements of time-resolved I*( P1/2) and CH3 fragment image...

The cumulative reaction probability ~CRP! has been calculated for the H21OH↔H2O1H in its full dimensionality by using the centrifugal sudden ~CS! approximation for J.0. The Boltzmann average of the CRP provides the most accurate thermal rate constant to date for the title reaction on the Walch, Dunning, Schatz, Elgersma ~WDSE! potential energy surface ~PES!. It is found that the theoretical rat...

A variant of a new empirical method, enables one fo express a collinear triaromic potential energy surface as a Family of Morse curves along “natural” bond order coordinates orthogonal to the reaction coordinate. The procedure depends on a single adjustable parameter which is related to the barrier-s height. Because an analytical expression for the number of vibrational states of a Morse oscill...

In the present paper we report on an analysis of the fine structure of the first excited quartet T2g of Mn4+ ions which occupy the octahedral site in the Cs2GeF6 host crystal. The dynamic T2g⊗ (eg + t2g) Jahn–Teller effect is considered in details, including the Ham effect of the reduction of the spin-orbit splitting and displacements of the ligands due to the combined effect of the a1g and eg ...

This article describes a quantum mechanical reactive scattering program for atom–diatom chemical reactions that we have written during the past several years. The program uses a coupled-channel hyperspherical coordinate method to solve the Schrödinger equation for the motion of the three nuclei on a single Born–Oppenheimer potential energy surface. It has been tested for all possible deuterium-...