Biomedical subjects

R L Coldwell

Publications and source records attributed to R L Coldwell.

4 recordsLinked to original sources

PubMed2006

Oscillator strengths of helium computed using Monte Carlo methods.

We have optimized trial wave functions for the three lowest states of the helium atom with symmetry 1S, 1P, 1D, 3S, 3P, and 3D using variational Monte Carlo methods. With these wave functions we then computed dipole oscillator strengths for the 1S-1P, 1P-1D, 3S-3P, and 3P-3D transitions using the length, velocity, and acceleration forms. Our values are in good agreement with the best results found in the literature.

Journal Article↗

PubMed2004

A ground state potential energy surface for H2 using Monte Carlo methods.

Using variational Monte Carlo and a simple explicitly correlated wave function we have computed the Born-Oppenheimer energy of the H2 ground state (X 1Sigmag+) at 24 internuclear distances. We have also calculated the diagonal correction to the Born-Oppenheimer approximation and the lowest-order relativistic corrections at each distance using variational Monte Carlo techniques. The nonadiabatic values are evaluated from numerical derivatives of the wave function with respect to the nuclear coordinates. With this potential energy surface we have computed several of the lowest vibrational-rotational energies for this system. Our results are in good agreement with the best values found in the literature.

Journal Article↗

PubMed2004

Properties of selected diatomics using variational Monte Carlo methods.

Using variational Monte Carlo and highly accurate trial wave functions optimized by Filippi and Umrigar, we calculate a number of molecular properties for the ground state of Li2, Be2, B2, C2, N2, O2, and F2. This is the first time that many of these properties have been computed.

Journal Article↗

PubMed1999

Relativistic calculations using Monte Carlo methods: one-electron systems.

Variance minimization and Monte Carlo integration are used to evaluate the four-component Dirac equation for a number of one-electron atomic and diatomic systems. This combination produces accurate energies, is relatively simple to implement, and exhibits few of the problems associated with traditional techniques.

Journal Article↗