Journal ArticleDOI
Force Constants and Dipole-Moment Derivatives of Molecules from Perturbed Hartree-Fock Calculations. I
J. Gerratt,Ian Mills +1 more
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In this article, the Hartree-Fock wave function was used as an approximate wave function for the direct calculation of force constants and dipole-moment derivatives from SCF-MO wavefunctions.Abstract:
General expressions for the force constants and dipole‐moment derivatives of molecules are derived, and the problems arising in their practical application are reviewed. Great emphasis is placed on the use of the Hartree–Fock function as an approximate wavefunction, and a number of its properties are discussed and re‐emphasised. The main content of this paper is the development of a perturbed Hartree–Fock theory that makes possible the direct calculation of force constants and dipole‐moment derivatives from SCF–MO wavefunctions. Essentially the theory yields ∂φi / ∂RJα, the derivative of an MO with respect to a nuclear coordinate.read more
Citations
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Polarized basis sets and the calculation of infrared intensities from nuclear electric shielding tensors
TL;DR: In this article, the idea of basis set polarization is applied to the calculation of the dipole moment derivatives with respect to nuclear displacements, and a polarized basis set of 26 CGTO's derived from the minimal CGTO basis set provides fairly reasonable results.
Book ChapterDOI
Spin-Hamiltonian Parameters from First Principle Calculations: Theory and Application
Journal ArticleDOI
Derivative couplings and analytic gradients for diabatic states, with an implementation for Boys-localized configuration-interaction singles.
TL;DR: It is demonstrated that Boys-localized diabaticStates do indeed exhibit small derivative couplings, as is required of quasidiabatic states, and a general formalism for calculating derivative coupling and analytic gradients for diabatics states is presented.
Journal ArticleDOI
Second-order coupled perturbed hartree—fock equations for closed-shell and open-shell self-consistent-field wavefunctions
TL;DR: In this article, the second-order coupled perturbed Hartree-Fock (CPHF) equations are used to analyze the second and higher derivatives of the total electronic energy for molecular systems.
Journal ArticleDOI
SCF dipole moment derivatives, harmonic frequencies and infrared intensities for C2H2 and C2H4
TL;DR: In this paper, analytical derivative techniques were used to obtain the dipole moment derivatives and harmonic frequencies of C 2H 2 and C 2 H 4 using SCF wavefunctions and large basis sets.
References
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Book
Dynamical Theory of Crystal Lattices
Max Born,Kʿun Huang +1 more
TL;DR: Born and Huang's classic work on the dynamics of crystal lattices was published over thirty years ago, and it remains the definitive treatment of the subject as mentioned in this paper. But it is not the most complete work on crystal lattice dynamics.
Journal ArticleDOI
Forces in molecules
TL;DR: In this article, it was shown that the force on a nucleus in an atomic system is just the classical electrostatic force that would be exerted on this nucleus by other nuclei and by the electrons' charge distribution.