The conformational stability of hexahydropyridobenzodioxin and related derivatives in both protonated and non-protonated forms have been investigated by means of ab initio molecular orbital methods as well as semi-empirical AM1 and PM3 methods. One of the cis conformers (cis2e) has been found to be most stable due to the formation of an intramolecular hydrogen bond, other conformers including t...

We present two new methods for molecular dynamics simulations based on general HartreeFock (GHF) theory. The first method involves approximating ab initio STO-3G matrix elements with fitting functions to enable faster computation of the energy and forces for molecular dynamics simulations. The implementation of this method includes a frozen-core approximation. The second method involves develop...

The van der Waals coefficients, C6 , C8, and C10 for the alkali-metal ~Li, Na, K, and Rb! and alkaline-earthmetal ~Be, Mg, Ca, and Sr! atoms are estimated by a combination of ab initio and semiempirical methods. Polarizabilities and atom-wall coefficients are given as a diagnostic check, and the lowest order nonadiabatic dispersion coefficient, D8 and the three-body coefficient, C9 are also pre...

A new force field has been customized for the variation of polynorbornene that contains a bicycloheptane group in the backbone structure. The force field was developed from ab initio density functional theory (DFT), and semiempirical electronic structure calculations for both stereochemical dimers of the 2,3 exoexo isomer of polynorbornene. The bond length and bond angle parameters were determi...

Diffusion coupling between different chemical components can have significant effects on the distribution of chemical species and can affect the physico-chemical properties of their supporting medium. The coupling can arise from local electric charge conservation for ions or from bound components forming compounds. We present a new lattice Boltzmann model to account for the diffusive coupling b...

In this research, a semi empirical approach has been suggested for calculating the activation energyof unimolecular thermal decomposition of vinyl ethers yielding saturated products. The calculationprocedure is based on the use of molecular mechanics (MM) methods. These methods which involvethe construction of the transition state for a molecule mainly consider the formation of a “HydrogenBridg...