We wish to perform a direct-SCF calculation equivalent to that above. A valid data sequence for performing such a calculation is shown below:
TITLE H2CO - EXTENDED TZVP BASIS - DIRECT-SCF ZMATRIX ANGSTROM C O 1 1.203 H 1 1.099 2 121.8 H 1 1.099 2 121.8 3 180.0 END BASIS TZVP SCFTYPE DIRECT RHF ENTERNote that the SCFTYPE directive is now required in requesting the DIRECT option. The third parameter on the data line, RHF, points to the particular category of wavefunction required i.e. closed-shell SCF. The options supported in direct-mode include RHF, UHF, GVB and MP2 (see below). Omitting this parameter and presenting just the line SCFTYPE DIRECT will lead to the default option of a direct-RHF calculation for closed-shell systems. Note that the default file output in such calculations is confined to ED3 and ED7, the Dump- and Scratch-file respectively.