2008/11/13 by Sridhar Sahu, Alok Shukla
Chemistry · Physics and Astronomy · #Ab initio #Advanced Chemical Physics Studies #Advanced Physical and Chemical Molecular Interactions #Atomic orbital #Atomic physics #CNDO/2 #Chemistry #Computational chemistry #Computer science #Dipole #Electron #Fortran #Hartree–Fock method #Molecular orbital #Molecule #Physics #Population #Quantum mechanics #Spectroscopy and Quantum Chemical Studies #cond-mat.mtrl-sci #physics.atm-clus #physics.comp-ph
paper · pdf · doi:10.1016/j.cpc.2008.11.004
published as Comp. Phys. Comm. 180, 724 (2009) · 29 pages, 3 figures, to appear in Computer Physics Communications
openalex publication_date 2008/11/13 · arxiv created 2008/12/19 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Despite the tremendous advances made by the ab initio theory of electronic structure of atoms and molecules, its applications are still not possible for very large systems. Therefore, semi-empirical model Hamiltonians based on the zero-differential overlap (ZDO) approach such as the Pariser-Parr-Pople, CNDO, INDO, etc. provide attractive, and computationally tractable, alternatives to the ab initio treatment of large systems. In this paper we describe a Fortran 90 computer program developed by us, that uses CNDO/2 and INDO methods to solve Hartree-Fock(HF) equation for molecular systems. The INDO method can be used for the molecules containing the first-row atoms, while the CNDO/2 method is applicable to those containing both the first-, and the second-row, atoms. We have paid particular attention to computational efficiency while developing the code, and, therefore, it allows us to perform calculations on large molecules such as C60 on small computers within a matter of seconds. Besides being able to compute the molecular orbitals and total energies, our code is also able to compute properties such as the electric dipole moment, Mulliken population analysis, and linear optical absorption spectrum of the system. We also demonstrate how the program can be used to compute the total energy per unit cell of a polymer. The applications presented in this paper include small organic and inorganic molecules, fullerene C60, and model polymeric systems, viz., chains containing alternating boron and nitrogen atoms (BN chain), and carbon atoms (C chain).