Molecular potential energy surface changes

Raman Studies of Molecular Potential Energy Surface Changes in Supercritical Fluids... 

BEN-AMOTZ ET AL. Molecular Potential Energy Surface Changes... 

D Ben-Amotz, F LaPlant, D Shea, J Gardecki, D List. Raman studies of molecular potential energy surface changes in supercritical fluids. ACS Symp Ser 488 18, 1991. 

By taking as a reference the calculation in vacuo, the presence of the solvent introduces several complications. In fact, besides the direct effect of the solvent on the solute electronic distribution (which implies changes in the solute properties, i.e. dipole moment, polarizability and higher order responses), it should be taken into account that indirect solvent effects exist, i.e. the solvent reaction field perturbs the molecular potential energy surface (PES). This implies that the molecular geometry of the solute (the PES minima) and vibrational frequencies (the PES curvature around minima in the harmonic approximation) are affected by the presence of a solvating environment. Also, the dynamics of the solvent molecules around the solute (the so-called nonequilibrium effect ) has to be... 

The vast majority of quantum chemical studies focus on equilibrium properties. However, a detailed understanding of chemical reactions requires a description of their chemical dynamics, which in turn requires information about the change in potential energy as bonds are broken or formed. Even though modem electronic structure theory can provide near-spectroscopic accuracy for small molecular systems near their equilibrium geometries, the general description of potential energy surfaces away from equilibrium remains very much a frontier area of research. 

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