The calculation of vertical electronic transition energies of molecular systems in solution with accurate quantum mechanical methods requires the use of approximate and yet reliable models to describe the effect of the solvent on the electronic structure of the solute. The polarizable continuum model (PCM) of solvation represents a computationally efficient way to describe this effect, especial...

The reaction of ammonia and pyridine with trimethylsulfonium ion has been studied in gas phase and solution. Density functional theory at the B3LYP/6-31+G level was used to describe the energy changes along the reaction coordinate in the gas phase, and the self-consistent isodensity polarizable continuum model (SCI-PCM) was used to calculate the effect of cyclohexane and dimethyl sulfoxide as t...

This study investigated the effects of solvents’ polarities on the geometry and electronic properties of 2-(2-nitrovinyl) furan, (NVF). The investigation was carried via theoretical approach, using an ab-initio [Hartree Fock (HF/6-31G*)] and Density Functional Theory (DFT/B3LYP/6-31G*).The properties investigated are optimized structures, energy gaps (ELUMO – EHOMO) and as...

To investigate the structural and thermodynamic basis of the binding of solvent at internal sites within proteins a number of mutations were constructed in T4 lysozyme. Some of these were designed to introduce new solvent-binding sites. Others were intended to displace solvent from preexisting sites. In one case Val-149 was replaced with alanine, serine, cysteine, threonine, isoleucine, and gly...

Linear-response theory is used to derive a microscopic formula for the free-energy change of a solutesolvent system in response to a change in the charge distribution of the solutes. The formula expresses the change in the solvent polarization energy as a quadratic function of the changes in the partial charges at the atomic centers of the solute atoms. The average electrostatic potential at th...

To explore the origin of the large-scale motion of triosephosphate isomerase's flexible loop (residues 166 to 176) at the active site, several simulation protocols are employed both for the free enzyme in vacuo and for the free enzyme with some solvent modeling: high-temperature Langevin dynamics simulations, sampling by a "dynamics driver" approach, and potential-energy surface calculations. O...

The understanding of the effect of a solvent on proton transfer requires the elucidation of the solvent contribution to the free energy of solvation. Due to the high dimensionality of the configuration space involved in the problem, the solvent effect can only be modeled via computer simulation for a complex polyatomic solute. While simulation of rather large systems have recently become relati...

1399) Topology of the potential energy surface (PES) along the PT and ET reaction coordinates (q p and q e) predicted by the theory with no solvent overlap (q e and q p orthogonal,) and at the condition pH = pK a (AH) and E applied = E CPET = E ET. The solvent overlap ̅ í µí¼† = 0 quantifies the coupling between the solvent modes along the PT and ET reaction coordinates. The SPET is kinetically ...