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468. QATREX: Relativistically Parameterized Extended
Hückel Program Employing Quaternionic Algebra
by Notker Rösch, Lehrstuhl für Theoretische Chemie, Technische Universität München, D-8046 Garching, FRG This program performs REX calculations as described by L. L. Lohr, Jr. and P. Pyykkö, Chem. Phys. Lett., 62, 333 (1979). The program exhibits all features of QCPE 387 from which it has been constructed, but differs from its precursor in the following: 1. Time reversal symmetry is fully taken into account during diagonalization by employing quaternionic algebra, as shown by N. Rösch, Chem. Phys. (in press). One quaternionic eigenvector represents both spin orbitals of a Kramers degenerate pair. 2. The code has been reorganized at various places (especially in the calculation of the overlap matrix) to further reduce core space and execution time. 3. The code fulfills (with two rather minor exceptions which have been indicated) the ANSI standard of FORTRAN 77 The current version is dimensioned for molecules with up to 30 atoms and, at most, 100 spin orbitals. About 40K words of core memory are required (plus I/O buffers). Instructions for changing dimensions and for constructing the input are given as COMMENT cards in the main program. The program uses one sequential scratch file. FORTRAN 77 (CDC FTN5) Lines of Code: 3900 |