This manual is designed for use with the ab initio quantum chemistry software package MOLCAS 5.0 [] developed at the Department of Theoretical Chemistry, Lund University, Sweden. MOLCAS is designed for use by theoretical chemists. It requires knowledge of the chemistry involved in the calculations in order to produce and interpret the results. The package is moderately difficult to use because of this `knowledge requirement' but the results are often more meaningful than those produced by ``blackbox" packages which are not as chemically precise in their input.
The MOLCAS 5.0 User's Guide contains a complete listing of the input keywords for each of the program modules and a information regarding files used in each calculation. It will be useful to the regular MOLCAS 5.0 user who wishes to check an input format for a keyword.
This volume, the MOLCAS 5.0 Help Guide, is designed for novice and intermediate users and is divided into two parts. Firstly, there are tutorials for most of the program modules available. These tutorials are designed for the first time user. Simple and easy to follow examples are presented for many of the modules contained in MOLCAS. The systems covered are not necessarily calculated with suitable methods or producing any significant results. There are, however, tips for the beginner and actual input file formats.
Secondly, there is a number of examples. These are outlines of actual research performed using MOLCAS. The approach to a research project is outlined including input files and shell scripts. More importantly, however, the value of the calculations is evaluated and advanced features of 5.0 are used and explained to improve the value of the results.
The user will find most of the scripts and input used in the present manual in the MOLCAS directories: $MOLCAS/tutorials, $MOLCAS/examples, and $MOLCAS/verifica, together with other test cases for the MOLCAS programs.