2MOLCAS as a development platform for quantum chemistry software

This work presents the quantum chemistry package MOLCAS, with emphasis on its usefulness as a platform for developing new quantum chemical codes, and the reader is assumed to be familiar with such a process. The development of new codes for quantum chemistry is a time-consuming job that can be dramatically simplified by using libraries for standard problems (such as calculation of integrals), and tools to surmount computer language and operating system limitations. The MOLCAS quantum chemistry software contains modules for a variety of quantum chemical methods, such as Hartree-Fock (HF), density functional theory (DFT), coupled-cluster (CC), and multiconfigurational (MCSCF) approaches, including second-order perturbation theory. It runs on almost all UNIX-like platforms and contains a single source code for 32- and 64-bit architecture, as well as for serial and parallel execution. The MOLCAS environment allows the user to include, in a simple way, new codes integrated with libraries and other MOLCAS modules. The key features of the MOLCAS environment include a modular structure, an easy-to-use environment, an application programming interface (API) library for solving common computational and system-oriented problems, a solid verification control system, and tools for a distributed development. (C) 2004 Wiley Periodicals, Inc.