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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TLDR
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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Book ChapterDOI
Many-Body Perturbation Theory for Vibrational-Electronic Molecular Hamiltonian
Ivan Hubač,Michal Svrček +1 more
TL;DR: The analytical evaluation of energy derivatives is one of the faremost achievements of modern ab initio quantum chemistry (1, 3, 4, 5, 6, 7, 8, 9, 10, this paper ).
Journal ArticleDOI
Analytic gradients for the combined sr-DFT/lr-MP2 method: application to weakly bound systems
TL;DR: In this paper, the formalism for analytical gradients in short-range density functional schemes with long-range ab initio corrections (sr-DFT/lr-ab initio) is presented.
Book ChapterDOI
Application of the CI-Singles Method in Predicting the Energy, Properties, and Reactivity of Molecules in Their Excited States
TL;DR: In this article, the capabilities and limitations of configuration interaction with all single excited determinants are illustrated by calculations on the excitation energies of benzene, bicyclobutane and Li2Na2, optimized geometry and properties of n-π* excited state of formaldehyde, vibrational frequencies of nπ * excited acrolein, and excited state potential energy curves for breaking σ and π bonds.
Journal ArticleDOI
General technique for analytical derivatives of post-projected Hartree-Fock
TL;DR: This work devises the analytic gradients of post-PHF approaches with a special focus on spin-extended (spin-projected) configuration interaction with single and double substitutions (ECISD).
Journal ArticleDOI
Efficient calculation of the density response function from generalized polarizabilities
TL;DR: In this article, generalized polarizabilities (GPs) were used to calculate the density response function (DRF) in the static limit and the number of coupled- perturbed self-consistent fi eld (CP-SCF) calculations in their method is proportional to the molecular volume at a given spatial resolution, and is independent of the basis set size.
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.