Efficient generation of distributed spherical Gaussian basis sets for molecules

Abstract

AbstractAn attempt is made to generate the spherical Gaussian distributed basis sets whose parameters are determined by means of a compromise between fully empirical prescriptions and fully optimized procedure. A hypersurface of the energy in a space of nonlinear Gaussian parameters for the molecular ion H and the H2, LiH, and He2 molecules is carefully analyzed, which allows us to propose a practical scheme for generation of nearly optimal basis sets. Three fundamental elements important for the construction of distributed molecular basis sets are discussed: orbital exponents, positions of basis set functions, and their partition of the localized subsets. Parameters generating nearly optimal exponents and positions of the basis functions are introduced. The set of the employed generating parameters is smaller than the original set of the exponents and positions by about three times. The designed basis sets defined by only 12 nonlinear parameters provide sub‐μhartree accuracy of three low‐lying states of H. Similarly, sub‐μhartree accuracy is achieved for the Hartree–Fock energy of H2, LiH, and He2 in the ground electronic state. Simple rules of the parameter reduction found for these molecules can be used for other molecules. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005