Simulation of Multifrequency EPR Spectra from Mn(III)/Mn(IV) Catalase of Lactobacillus plantarum Using a New Approach Based on Perturbation Theory

1994 ◽  
Vol 33 (12) ◽  
pp. 2677-2682 ◽  
Author(s):  
Alice Haddy ◽  
Geoffrey S. Waldo ◽  
Richard H. Sands ◽  
James E. Penner-Hahn
Keyword(s):  
Perturbation Theory ◽  
Lactobacillus Plantarum ◽  
Epr Spectra ◽  
New Approach

New Approach to Perturbation Theory.

1979 ◽  
Vol 43 (2) ◽  
pp. 176-176 ◽  
Author(s):  
Y. Aharonov ◽  
C. K. Au
Keyword(s):  
Perturbation Theory ◽  
New Approach

An Automatic Differentiation and Diagrammatic Notation Approach for Developing Analytical Gradients of Tensor Hyper-Contracted Electronic Structure Methods

2020 ◽  
Author(s):  
Chenchen Song ◽  
Todd J. Martínez ◽  
Jeffrey B. Neaton
Keyword(s):  
Perturbation Theory ◽  
Electronic Structure ◽  
Automatic Differentiation ◽  
Nonadiabatic Coupling ◽  
New Approach ◽  
Future Developments ◽  
Memory Footprint ◽  
Electronic Structure Methods ◽  
Tensor Contraction ◽  
Analytical Gradients

We show how the combination of automatic differentiation (AD) and diagrammatic notation can facilitate the development of analytical nuclear derivatives for tensor hyper-contraction based (THC) electronic structure methods. The automatically-derived gradients are guaranteed to have the same scaling in terms of both operation count and memory footprint as the underlying energy calculations, and the computation of a gradient is roughly three times as costly as the underlying energy. The new AD/diagrammatic approach enables the first cubic scaling implementation of nuclear derivatives for THC tensors fitted in molecular orbital basis (MO-THC). Furthermore, application of this new approach to THC-MP2 analytical gradients leads to an implementation which is at least four times faster than the previously reported, manually-derived implementation. Finally, we apply the new approach to the 14 tensor contraction patterns appearing in the supporting subspace formulation of multireference perturbation theory, laying the foundation for future developments of analytical nuclear gradients and nonadiabatic coupling vectors for multi-state CASPT2. <br>

ENERGY SPECTRUM OF MOTT–WANNIER EXCITON STUDIED BY VIRTUE OF THE EXCITON ENTANGLED STATE REPRESENTATION INSTEAD OF K·P PERTURBATION THEORY

2005 ◽  
Vol 19 (13n14) ◽  
pp. 637-642 ◽  
Author(s):  
HONG-YI FAN ◽  
HUI ZOU ◽  
YUE FAN ◽  
QIU-YU LIU
Keyword(s):  
Perturbation Theory ◽  
Energy Spectrum ◽  
Entangled State ◽  
Entangled State Representation ◽  
State Representation ◽  
New Approach

We introduce the exciton entangled state. We show that the energy spectrum of Mott–Wannier exciton can be exactly derived by virtue of the entangled state representation. In contrast to the K · P perturbation theory this new approach seems non-perturbative, direct and exact.

Sign in / Sign up

Export Citation Format

Share Document