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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Excited-State Geometry Optimization with the Density Matrix Renormalization Group, as Applied to Polyenes
Weifeng Hu,Garnet Kin-Lic Chan +1 more
TL;DR: In this article, a wave function maximum overlap following technique was introduced to facilitate state-specific DMRG excited-state optimization, and the low-lying singlet states of a series of trans-polyenes up to C_(20)H_(22) were investigated.
Journal ArticleDOI
Analytic configuration interaction (CI) gradient techniques for potential energy hypersurfaces. A method for open-shell molecular wave functions
TL;DR: In this paper, a formalism is presented for the determination of analytic energy first derivatives for the most common types of open-shell correlated wave functions, for which the electronic structure is qualitatively understood in terms of a set of molecular orbitals which are eigenfunctions of Roothaan's restricted Hartree-Fock (RHF) operator.
Journal ArticleDOI
Analytic energy gradients for general coupled‐cluster methods and fourth‐order many‐body perturbation theory
TL;DR: In this paper, the gradient equations for the full fourth-order many-body perturbation energy were derived, and the gradient procedure was shown to be an n7 process in the number of basis functions.
Journal ArticleDOI
A numerically stable procedure for calculating Moller-Plesset energy derivatives, derived using the theory of Lagrangians
TL;DR: In this paper, a non-canonical Lagrangian of the second-order Moller-Plesset energy was derived for the molecular gradient and Hessian of an energy derivative constructed in a noncanonical representation, and it was shown that the most expensive step in the calculation of the Hessian scales as Mn4o.
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A vibrational circular dichroism implementation within a Slater-type-orbital based density functional framework and its application to hexa- and hepta-helicenes
TL;DR: In this paper, the authors describe the implementation of the rotational strengths for vibrational circular dichroism (VCD) in the Slater-type orbital based Amsterdam density functional (ADF) package.
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.