Third and Fourth Derivatives of the Hartree-Fock Energy: Formalism and Applications

Author(s):  
J. F. Gaw ◽  
N. C. Handy
Keyword(s):  
2015 ◽  
Vol 113 (13-14) ◽  
pp. 1961-1977 ◽  
Author(s):  
Dmytro Bykov ◽  
Taras Petrenko ◽  
Róbert Izsák ◽  
Simone Kossmann ◽  
Ute Becker ◽  
...  

2018 ◽  
Vol 17 (05) ◽  
pp. 1850037 ◽  
Author(s):  
Oinam Romesh Meitei ◽  
Andreas Heßelmann

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.


2017 ◽  
Vol 146 (7) ◽  
pp. 074104 ◽  
Author(s):  
Takashi Tsuchimochi ◽  
Seiichiro Ten-no

1972 ◽  
Vol 57 (8) ◽  
pp. 3337-3340 ◽  
Author(s):  
Péter Pulay ◽  
Wilfried Meyer

2021 ◽  
Vol 316 ◽  
pp. 75-80
Author(s):  
Oleg Kh. Karimov ◽  
Galina Yu. Kolchina ◽  
Eldar M. Movsumzade

In the framework of method of the B3LYP hybrid density functional and the restricted Hartree-Fock method, quantum-chemical calculations of model compounds of lignin, i.e. derivatives of p-hydroxycinnamic alcohol were carried out. The structures and reactivity of coumaric, coniferyl and synapol alcohols were studied. Quantitative characteristics of the reactivity of these acids are given. It is found that the electronic structure of lignin is determined primarily by the charge distribution in its structural phenylpropane unit. In the molecules of all model compounds of lignin, the center for nucleophilic attack is the carbon of aromatic ring (E-ring) with a hydroxyl group, and in the molecule of synapol alcohol, this center is also the carbon of the aromatic ring (E-ring) with a methoxy group. In all three compounds, a center with an increased electron density appears on the Сβ carbon atom.


Sign in / Sign up

Export Citation Format

Share Document