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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Molecular properties from perturbation theory: a unified treatment of energy derivatives
Jan Almlöf,Peter R. Taylor +1 more
TL;DR: In this paper, the definition of a molecular property as a derivative of the electronic energy with respect to one or more applied perturbations is reviewed, and explicit enumeration of terms entering the derivative formulas is performed by considering in turn the various parameter spaces on which the energy and wave function depend.
Journal ArticleDOI
Calculations of the force field of the methane molecule
TL;DR: In this paper, the SCF and CAS SCF calculations have been carried out to determine the quadratic and some of the higher force constants of the methane molecule, and the calculated SCF value of r e is 1·08258 A which is very close to Gray and Robiette's experimental value of 1·0·0010 A.
Journal ArticleDOI
A comparison of ab initio optical rotations obtained with static and dynamic methods
TL;DR: In this paper, the optical rotations of several chiral molecules have been calculated with both static and dynamic methods and these predictions are compared to the experimental optical rotation signs predicted by the static method and the dynamic method with London orbitals.
Journal ArticleDOI
Energy derivatives for configuration interaction wave functions
TL;DR: In this paper, the first and second derivatives of a configuration interaction energy with respect to an external parameter were derived for a general multiconfiguration Hartree-Fock wave function.
Journal ArticleDOI
Semiempirical Quantum-Chemical Orthogonalization-Corrected Methods: Benchmarks of Electronically Excited States.
TL;DR: It is found that the current OMx/MRCI methods perform reasonably well for many of the excited-state properties, however, in comparison to the first-principles methods, there are also a number of shortcomings that should be addressed in future developments.
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.