AB-INITIO HARTREE-FOCK SELF-CONSISTENT-FIELD CALCULATIONS - AN INDIGENOUS DEVELOPMENT OF COMPUTER-PROGRAMS

A set of indigenously developed computer programs for ab-initio Hartre e-Fock calculations on both closed- and open-shell molecules have been described. These programs have been written for calculations using GT O basis sets. Integral formulae have been taken from Taketa et al [8]. Structures and functions of the programs have been discussed. These p rograms have been extensively tested. Molecular integrals over GTO bas is sets have been chosen for tests and as numerical examples in this p aper. Results of calculations using very accurate minimal bases have b een given for methane. Time taken for these computations in a CDC Cybe r 180/840 machine has been indicated. Trends in the calculations have also been illustrated by employing 4-gaussian expansions for the STO's and by varying the basis size for LiH and BH+.