scholarly journals General technique for analytical derivatives of post-projected Hartree-Fock

2017 ◽  
Vol 146 (7) ◽  
pp. 074104 ◽  
Author(s):  
Takashi Tsuchimochi ◽  
Seiichiro Ten-no
Keyword(s):  
General Technique ◽  
Hartree Fock ◽  
Analytical Derivatives ◽  
Derivatives Of

Concerning analytical derivatives of kinetic and potential energies in the Hartree–Fock theory

1992 ◽  
Vol 96 (8) ◽  
pp. 6018-6025 ◽  
Author(s):  
Hiroaki Tokiwa ◽  
Hiroshi Ichikawa ◽  
Yoshihiro Osamura
Keyword(s):  
Hartree Fock ◽  
Analytical Derivatives ◽  
Derivatives Of ◽  
Kinetic And Potential Energies

Efficient implementation of the analytic second derivatives of Hartree–Fock and hybrid DFT energies: a detailed analysis of different approximations

2015 ◽  
Vol 113 (13-14) ◽  
pp. 1961-1977 ◽  
Author(s):  
Dmytro Bykov ◽  
Taras Petrenko ◽  
Róbert Izsák ◽  
Simone Kossmann ◽  
Ute Becker ◽  
...  
Keyword(s):  
Detailed Analysis ◽  
Efficient Implementation ◽  
Hartree Fock ◽  
Second Derivatives ◽  
Derivatives Of

Geometry optimizations with the incremental molecular fragmentation method

2018 ◽  
Vol 17 (05) ◽  
pp. 1850037 ◽  
Author(s):  
Oinam Romesh Meitei ◽  
Andreas Heßelmann
Keyword(s):  
Nuclear Energy ◽  
Energy Surface ◽  
Chem Phys ◽  
Theory Method ◽  
Molecular Fragmentation ◽  
Hartree Fock ◽  
Moller Plesset ◽  
Derivatives Of ◽  
Plesset Perturbation Theory ◽  
The Imf

Nuclear energy gradients for the incremental molecular fragmentation (IMF) method presented in our previous work [Meitei OR, Heßelmann A, Molecular energies from an incremental fragmentation method, J Chem Phys 144(8):084109, 2016] have been derived. Using the second-order Møller–Plesset perturbation theory method to describe the bonded and nonbonded energy and gradient contributions and the uncorrelated Hartree–Fock method to describe the correction increment, it is shown that the IMF gradient can be easily computed by a sum of the underlying individual derivatives of the energy contributions. The performance of the method has been compared against the supermolecular method by optimizing the structures of a range of polyglycine molecules with up to 36 glycine residues in the chain. It is shown that with a sensible set of parameters used in the fragmentation the supermolecular structures can be fairly well reproduced. In a few cases the optimization with the IMF method leads to structures that differ from the supermolecular ones. It was found, however, that these are more stable geometries also on the supermolecular potential energy surface.

scholarly journals Speeding-up the Fitting of the Model Defining the Ribs-bounded Contour

2017 ◽  
Vol 21 (1) ◽  
pp. 66-70
Author(s):  
Mykolas J. Bilinskas ◽  
Gintautas Dzemyda ◽  
Martynas Sabaliauskas
Keyword(s):  
Mathematical Model ◽  
Local Search ◽  
Computer Tomography ◽  
Vertical Axis ◽  
Newton Methods ◽  
Optimal Parameters ◽  
Analytical Derivatives ◽  
The Mathematical Model ◽  
Quasi Newton ◽  
Derivatives Of

Abstract The method for analysing transversal plane images from computer tomography scans is considered in the paper. This method allows not only approximating ribs-bounded contour but also evaluating patient rotation around the vertical axis during a scan. In this method, a mathematical model describing the ribs-bounded contour was created and the problem of approximation has been solved by finding the optimal parameters of the mathematical model using least-squares-type objective function. The local search has been per-formed using local descent by quasi-Newton methods. The benefits of analytical derivatives of the function are disclosed in the paper.

Sign in / Sign up

Export Citation Format

Share Document