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 static and dynamic structure of liquid lithium (470 K) in a computer experiment were investigated using a new type of interaction: the pair potential is constructed from an ab initio molecular dynamics method which makes the effective interionic potential self-consistent with the radial distribution functions on the basis of the quantd hypemetted-chain theory. Comparisons of the new calcula...

Hydroxyapatite (HAP) and fluorapatite (FAP) are essential components of dental enamel and bone. In this paper, we report a computational study of the elastic properties of HAP and FAP using ab initio and force field techniques. We have obtained the HAP and FAP elastic stiffness constants in hexagonal symmetry by fitting the Hooke law for both the energy-strain and stress-strain relations. Our a...

We present an overview of recent results and developments of the no-core shell model (NCSM), an ab initio approach to the nuclear many-body problem for light nuclei. In this approach, we start from realistic two-nucleon or twoplus threenucleon interactions. Many-body calculations are performed using a finite harmonicoscillator (HO) basis. To facilitate convergence for realistic inter-nucleon in...

We have introduced a computational methodology to study vibrational spectroscopy in clusters inclusive of critical nuclear quantum effects. This approach is based on the recently developed quantum wavepacket ab initio molecular dynamics method that combines quantum wavepacket dynamics with ab initio molecular dynamics. The computational efficiency of the dynamical procedure is drastically impro...