14.2 The basis set library

The basis set library consists of a set of plain text files, together with an associated index, that constitute a database of commonly-used basis sets (primitive gaussians and associated contractions) and effective core potentials. These files can be found in the source tree as lib/*.libmol and lib/libmol.index, but it is usually more convenient to query the database using one of the provided tools.

Many of the basis sets are taken directly from the Pacific Northwest National Laboratory basis set database, but there are others, notably the Stuttgart effective core potentials and bases.

A simple command-line interface to the database is provided through the libmol program. It requires the environment variable LIBMOL to point to the lib/ directory, but this will default to the location of the source tree at compile time, so it is often not necessary to specify it. The command-line syntax is

libmol [-p print] [-e element] [-k key] [-t type] [-f format]

where the parameters are

print:

Output level; 0 means list matching keys, 1 means print also the entry.

element:

Specify chemical element. If omitted, all elements are searched.

key:

Specify record key. If omitted, all keys are searched.

type:

Specify entry type, i.e. $s, p,\dots$. If omitted, all types are searched.

format:

One of text (default), molpro (MOLPRO input format), table (tabular) or html (html table) to govern the output format.

A more convenient way of browsing the basis library is through a web-based interface. The CGI script molpro_basis presents a graphical and forms based interface for performing searches. It may be installed locally, but is also normally available at

http://www.tc.bham.ac.uk/molpro/current/molpro_basis.