SEARCH Articles Figures Tables Appendix 8.2 Finite Difference Approximations Approximation techniques finite differences Convergence order finite difference approximations Crank—Nicholson finite difference approximation Finite difference approximation of the boundary-value problem Finite difference approximations Finite element approximation Finite-basis approximations. Closed-shell systems Finite-field approximation, optical properties Fukui function finite difference approximations Hartree-Fock approximation, finite-size The Finite Difference Approximation Truncation error, finite difference approximation Uniform approximation finite difference schemes