The MOLECULE-style input is originally based on the input for the MOLECULE integral program by Almlöf [126]. However, there are few remnants of the original input structure. For users of earlier releases of the Dalton program, note should be taken of the fact that the input structure for the MOLECULE file has undergone major changes, however, backward compatibility has in most cases been retained23.1. The program supports both Cartesian and Z-matrix input of the molecular coordinates. However, the Z-matrix input provided is only a convenient way of describing the molecular geometry, as the Z-matrix is converted to Cartesian coordinates, which are then used in the subsequent calculations. Note that the Z-matrix input can only be used together with the basis set library ("BASIS" in first line).
The program includes an extensive basis set
library, which are described below.
There are additional possibilities for choosing the number of primitive
and contracted orbitals to be used with the Atomic Natural Orbital
(ANO) basis sets
and the ``Not Quite van Duijneveldt'' (NQvD) basis
sets. The large number of
different basis sets provided is in part
related to the variety of molecular properties with very different
basis set requirements that can be calculated with DALTON.
Most of the basis sets have been downloaded from the EMSL basis set
library service
(http://www.emsl.pnl.gov:2080/forms/basisform.html) [127].
Only six of the basis sets were obtained from different sources:
We note that each file containing a given basis set in the BASIS directory contains the proper reference to be used when doing a calculation with a given basis set. For convenience we also list these references with the basis sets in Section 23.6.
The description of the MOLECULE input is divided into five parts. Section 23.1 describes the general section of the molecule input, section 23.2 describes the Cartesian coordinate input, section 23.3 describes the Z-matrix input, and finally Section 23.4 describes the basis set library. Section 23.6 lists the basis sets (including references and supported elements) in the basis set library.