Full configuration interaction (FCI) calculations are carried out using the Slater determinant-based algorithm by Knowles and Handy. The linear combination of Slater determinants for singlet states that they mentioned is exploited and timing data is reported. A test calculation is performed for the Li2 molecule. The Schrodinger equation for the nuclear motion is olved to obtain spectroscopic constants for AlH. The constants obtained are in agreement with experiment within error of 4% on average.
AM1 calculations were performed on the decomposition of ozone on an Ag (110) surface, and a new reaction mechanism was proposed. Two forms of atomic oxygen are produced when ozone dissociatively adsorbs on Ag (110). One form of the atomic oxygen then reacts with ozone to form an O4- (a) intermediate, which decomposes into two oxygen molecules. This is the first proposal that the 04- species has been included in this reaction.
Mechanisms of 0-0 bond cleavage and transfer of an oxygen atom to a substrate, from a proposed ultimate species for the monooxygenation reaction by P-450  were investigated using the first principle calculation with density functional theory (DFT) and PM3 method. If the substrate does not exist in the active site, cleavage of oxygen molecule binding at the 6th ligand site does not occur by reduction of two electrons and subsequent reaction with a couple of protons. The monooxygenation reaction occurs spontaneously by the reduction of two electrons and the subsequent reaction with two protons when there is an interaction between the oxygen molecule at the 6th ligand of heme and substrate. Application of this result to selective hydroxylation of C5 atom of d-camphor by P-450cam corresponds to experimental results; i.e., C5 atom hydroxylation occurred in one step with an activa-tion energy of 5.6 kcal/mol and is a possible reaction at body temperature. The oxygen atom transfer occurred at C9-H bond in unusual conditions in which the transfer did not occur at C5-H bond; e.g., replacement of hydrogen atoms binding C5 atom with fluorine atoms. Reaction with C4 atom which is near C5 atom did not occur because of large activation energy (9.8 kcal/mol).
Vibrational frequencies and infrared intensities of methane and four fluorinated methane molecules in the gas phase have been calculated with the ab initio molecular orbital method using various combinations of basis set functions and electron correlation correction methods, and compared with corresponding experimental values. The best combination of basis set function and electron correlation correction method is recomended.
The solid-liquid phase transition for Lennard-Jones system under constant volumeis studied by entropy sampling Monte Carlo (ESMC) method. Occupied volume per a molecule is fixed at σ3; σ is a diameter of molecule. The basic cell contains 108 molecules, located as distorted FCC lattice at initial configuration. Accumulated function J (E) converged by 124 iterations, one iteration consists of 10, 000 MC steps, and one MC step represents 108 moves. Estimated phase transition temperature corresponds to derivation from usual equation of state. Further, interaction part of the mean entropy of the system was estimated.
Molecular dynamics (MD) simulations of the diffusion of water in ethylene-vinylalcohol copolymer with various fractions of the ethylene component have been performed. The decay curves obtained by the torsional angle autocorrelation function (TACF) of the skeletal bonds and side chain indicated that the increase in the ethylene content significantly enhanced the chain flexibility. The translational self-diffusion coefficients, Dself, at 0.4% (g/g) water concentration increased in the order from 10-8 cm2/s to 10-6 cm2/s with an increase in the ethylene content due to the liberation of immobilized water from the side chain OH group. The increase in the water concentration enhanced the flexibility of the chain motion, which resulted in the increase in the diffusivity. The quantitative relation between the chain dynamics and diffusivity of water is reported in light of the cooperative motion of the penetrant molecules coupled with the side chain OH group.