NEW ALGORITHMS FOR AN INDIVIDUALLY SELECTING MR-CI PROGRAM

In the present work we discuss the main features of new algorithms to do individually-selecting MR-CI calculations. Employing a new program package we are able to perform calculations including more than two mi llion selected configuration state functions (CSFs) as a matter of rou tine. A test calculation on the C-6 molecule including about 2.3 mill. selected CSFs takes about 54 minutes on a PentiumPro for one iteratio n within the Davidson procedure. This enables one to study more compli cated and larger systems with a higher accuracy than before. (C) 1997 Elsevier Science B.V.