The KPACK program is intended for relativistic electronic structure computation of molecules containing heavy elements via the two-component ab initio calculations in Kramers restricted and unrestricted formalisms in the framework of the spin-orbit relativistic effective core potential (SOREP).The spin-orbit coupling as relativistic effect enters into the calculation at the Hartree-Fock level and hence, is treated in a variational manner to generate two-component molecular spinors as one-electron wavefunctions for use in the correlated methods. As correlated methods, KPACK currently provides the two-component second-order Møller-Plesset perturbation theory, configuration interaction, and complete active space self-consistent field methods. FeaturesAtomic orbital integrals- Supports both spherical and Cartesian gaussian basis sets (up to
*h*-functions) - One-electron integrals
- Overlap, kinetic, nuclear attraction integrals using Obara-Saika recurrence relations and Gauss-Hermite quadrature
- SOREP integrals (core potential, spin-orbit
*x*,*y*, and*z*integrals) - Two-electron integrals
- Electron repulsion integrals by the recursive algorithm through Rys polynomials
Self-consistent field- Kramers restricted and unrestricted Hartree-Fock (KRHF and KUHF)
- Diagonalization based on quaternion algebra
- Parallelized using OpenMP
- Two-component modified direct inversion in iterative subspace (DIIS) acceleration
Molecular spinor integrals- Complex two- and four-index transformation
- Kramers restricted and unrestricted molecular spinor integrals
- Eight distinct integral sets for KR spinors
- Two distinct integral sets for KU spinors
Perturbation theory- Kramers restricted and unrestricted second-order Møller-Plesset perturbation theory (KRMP2 and KUMP2)
Configuration interaction- Kramers restricted and unrestricted configuration interaction (KRCI and KUCI)
- Direct CI using extended Davidson diagonalization for Hermitian matrix
- Determinant construction via graph theory
- Spin-orbit CI is also possible
Multi-configurational self-consistent field- Kramers restricted complete active space self-consistent field (KRCASSCF)
- Full consideration of time-reversal symmetry
- Two-step near second-order approach for convergence
- Applicable for both closed- and open-shell systems
NewsJuly 30, 2014kpackprogram.org website is created. |