Van der Waals Force repository and database.

These pages are a repository giving information about interatomic forces at the long-ranges. The repository aims to provide links to important papers. The repository also gives reference atomic data that is used in the calculation of dispersion forces.

The material presented here is largely concerned with the calculation of dispersion forces when two atoms are a long distance apart. The tabulated information is presented in forms. One form consists of pseudo-oscillator strength distributions. The other form consists of dynamic polarizabilities computed at imaginary frequencies.

The focus of this resource is upon calculations that are based on the Schrodinger equation. Little attention is given to methods that using density functional theory to determine the dispersion coefficients.

Personnel.

Papers

Computer Programs.

There are two sets of data stored at this web site, (a) Pseudo-oscillator strength distributions and (b) dynamic polarizabilities. The pseudo-oscillator strength distributions represent the primary data.

There are three Fortran programs available for the processing of this data. First there is a program that reads the pseudo-oscillator strength data and computes the dynamic polarizabilities at imaginary frequencies. The program also outputs to file the quadrature grid for the frequency integrations.

Second there is a program designed to compute dispersion parameters using oscillator strength sum rules. One simply reads in the pseudo-oscillator strength distributions for two atoms and the dispersion coefficients for that pair of atoms is computed. The final program uses the dynamic polarizabilities to compute the dispersion parameters. This is reliant on having all the dynamic polarizabilities computed on the same frequency grid. All dynamic polarizabilities available here are computed on same grid. However, there may be cases where the dynamic polarizability might be is best computed with a another frequency grid. In these cases, it is possible to construct the dynamic polarizability on a different grid by editing Program 1. The grid used in the Derevianko et al tabulations:w (2010 At. Data. Nucl. Data Tables 96 323) is already programmed.

Data

Pseudo-oscillator strength distributions and dynamic polarizabilities have been collected for a number of atoms and atomic ions. These can be downloaded from the Programs and Data web-page.

Other groups interested in polarization, dispersion forces and/or atom-atom interactions

• Dr Li Yan Tang, Wuhan Institute of Physics and Mathematics, Wuhan, China
• Dr Marianna Safronova, University of Delaware
• Dr Andrei Derevianko, University of Nevada, Reno
• Dr James Babb, ITAMP (hosted at ANU)
• Dr E Tiemann, Institute of Quantum Optics, Hannover
• European cold Molecules Network
• Dr G Groenenboom, Institute for Molecules, Radboud Universirtm Nijmengen

Some useful sources of Atomic Data

• NIST PRD Databases, Gaithersburg, MD
  • Atomic Spectroscopy Databases
  • Atomic Energy Levels Database
  • Bibliographic Database on Atomic Transition Probabilities
  • Fundamental constants of Physics and Chemistry
• CFA, Atomic & Molecular Data for Astronomy