The H, system has excited much mterest both theoretically [l] and experimentally [2]. In particular It has been used to study elastic, inelastic and reacttve scattermg. The H3 molecule has been observed in an excited Rydberg state [3], a Bndtng confirmed by ab initio calculation [4,5], but as yet we know of no experimental evidence for it in its electronrc ground state. The ground-state potenti...

The observation of an infrared spectrum of the H +3 molecular ion at its dissociation limit by Carrington and co-workers has presented a tremendous challenge to theory. To compute this spectrum it is necessary to model accurately the global potential energy surface of H +3 , vibrationally excited states at dissociation, rotational excitation, lifetimes of rotationally excited `shape’ resonances...

A new four-dimensional potential energy surface for CO2-C2H2 complex has been calculated by the ab initio methods at MP2/cc-pVXZ and MP2/aug-cc-pVXZ theory. For calculating the PES of the CO2-C2H2 complex, we have chosen to follow the supermolecule approach. The complete basis set limit of potential energy surface has been taken by extrapolation. Our MP2 results showed the most stable form of C...

A three-dimensional, analytic potential energy surface for CO(2)-He that explicitly incorporates its dependence on the Q(3) asymmetric-stretch normal-mode coordinate of the CO(2) monomer has been obtained by least-squares fitting new ab initio interaction energies to a new three-dimensional Morse/Long-Range (3D-MLR) potential function form. This fit to 2832 points has a root-mean-square (RMS) d...

some of the adamantane properties were calculated in this study. chemical shift, free energy ofsolvation, free energy of cavity formation, henry's law constant, and other properties ofadamantane in dry phase, three solvents and three temperatures have been calculated with abinitio method base on density functional theory (dft) at b3lyp/6-31g, b31yp/6-31g*, b3lyp/6-31+g* and b3lyp/6-31++g** leve...

the intermolecular forces between water molecules are of great importance in many areas of chemistry including solvation, solution chemistry, and biochemistry. as a result of this (h2o)n systems have received a great significant of attention, both experimental and theoretical. all calculation of this study are carried out by gaussian 98 soft ware. geometry optimization for each cluster were be ...

Potential energy surfaces form a central concept in the application of electronic structure methods to the study of molecular structures, properties, and reactivities. Recent advances in tools for exploring potential energy surfaces are surveyed. Methods for geometry optimization of equilibrium structures, searching for transition states, following reaction paths and ab initio molecular dynamic...

We report a full dimensional, ab initio based potential energy surface for CH(5) (+). The ab initio electronic energies and gradients are obtained in direct-dynamics calculations using second-order Møller-Plesset perturbation theory with the correlation consistent polarized valence triple zeta basis. The potential energy and the dipole moment surfaces are fit using novel procedures that ensure ...

and valence bond method, solvent effects on S N 2 reaction, and Monte Carlo simulations of chemical reaction in solution. Abstract: A mixed molecular orbital and valence bond (MOVB) method is described in combined ab initio QM/MM simulations of the S N 2 reaction of Cl-+ CH 3 Cl _ ClCH 3 + Cl-in water. The method is based on the construction of individual charge-localized, diabatic states using...

A tight-binding total-energy (TBTE) method has been developed to interpolate between firstprinciples results describing the dissociation of molecules at surfaces. The TBTE scheme requires only a relatively small number of ab initio energies as input and gives a reliable global representation of the ab initio potential energy surface to within 0.1 eV accuracy compared to the ab initio results. T...