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Calculation of Coulomb interaction matrix elements in the basis of a two-dimensional harmonic oscillator (HO2D).

Download and unpack the latest release, then run:

make PREFIX=/usr/local install

Replace /usr/local with wherever you want it to be installed.

The code calculates the spatial part of the Coulomb interaction matrix element:

Here, φ[n, ml] denotes the eigenfunction of a two-dimensional harmonic oscillator with principal quantum number n and angular momentum projection ml. In polar coordinates, these functions may be defined in terms of the associated Laguerre polynomials L:

The library is designed to be extensible: calculation of the the matrix elements is fulfilled via a tabulation provider, a specialized executable that understands a certain file format and protocol. For details, see protocol.h and clh2-am.c.

The library has a default provider called clh2-am that is installed with the package. This provider use the analytic formula in Anisimovas & Matulis (1998), which yields a relatively simple implementation with no external dependencies. However, it can be quite slow and may be inaccurate for higher shells. You can substitute another provider easily by setting the provider argument when calling clh2_request.

If you'd like, you can install a different provider: clh2-openfci, which can be much faster and more accurate than the default provider.