Spin–spin coupling tensors by density-functional linear response theory

2002 ◽  
Vol 117 (13) ◽  
pp. 5998-6009 ◽  
Author(s):  
Perttu Lantto ◽  
Juha Vaara ◽  
Trygve Helgaker
Keyword(s):  
Linear Response ◽  
Density Functional ◽  
Linear Response Theory ◽  
Spin Coupling ◽  
Response Theory ◽  
Spin Spin Coupling

Indirect nuclear spin–spin coupling constants from multiconfiguration linear response theory

1992 ◽  
Vol 96 (8) ◽  
pp. 6120-6125 ◽  
Author(s):  
Olav Vahtras ◽  
Hans Ågren ◽  
Poul Jo/rgensen ◽  
Hans Jo/rgen Aa. Jensen ◽  
So/ren B. Padkjær ◽  
...  
Keyword(s):  
Nuclear Spin ◽  
Linear Response ◽  
Linear Response Theory ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Response Theory ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

Lattice dynamics properties of chalcopyrite ZnSnP 2 : Density-functional calculations by using a linear response theory

2017 ◽  
Vol 26 (4) ◽  
pp. 046302 ◽  
Author(s):  
You Yu ◽  
Yu-Jing Dong ◽  
Yan-Hong Shen ◽  
Guo-Dong Zhao ◽  
Xiao-Lin Zheng ◽  
...  
Keyword(s):  
Density Functional Calculations ◽  
Linear Response ◽  
Lattice Dynamics ◽  
Density Functional ◽  
Linear Response Theory ◽  
Response Theory

The von Weizsäcker Coefficient in Density Functional Theoryt

1976 ◽  
Vol 31 (8) ◽  
pp. 898-903 ◽  
Author(s):  
A. Meyer ◽  
Gwo-ching Wang ◽  
H. Young
Keyword(s):  
Harmonic Oscillator ◽  
Linear Response ◽  
Weak Coupling ◽  
Density Functional ◽  
Linear Response Theory ◽  
Weak Coupling Limit ◽  
Response Theory ◽  
Quality Of Results ◽  
Correct Energy

Abstract For any given potential, linear response theory tells us the size that the von Weizsäcker coefficient must assume in order to obtain the correct energy in the weak coupling limit. With this necessarily imposed choice, the quality of results is investigated as the coupling is strengthened. From the study of a number of model problems (the harmonic oscillator, the Yukawa well and the Mathieu potential) it is concluded that good results can be maintained to high couplings.

scholarly journals Comparison of Linear Response Theory, Projected Initial Maximum Overlap Method, and Molecular Dynamics Based Vibronic Spectra: The Case of Methylene Blue

2021 ◽  
Author(s):  
Ali Abou Taka ◽  
Shao-Yu Lu ◽  
Duncan Gowland ◽  
Tim J. Zuehlsdorff ◽  
Hector H. Corzo ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Absorption Spectra ◽  
Linear Response ◽  
Density Functional ◽  
Normal Modes ◽  
Vertical Gradient ◽  
Linear Response Theory ◽  
Response Theory ◽  
Vibronic Spectra ◽  
Overlap Method

Simulation of optical spectra is essential to molecular characterization and, in many cases, critical for interpreting experimental spectra. The most common method for simulating vibronic absorption spectra relies on the geometry optimization and computation of normal modes for ground and excited states. In this report, we show that utilization of such a procedure within an adiabatic linear response theory framework may lead to state mixings and a breakdown of the Born-Oppenheimer approximation, resulting in a poor description of absorption spectra. In contrast, computing excited states via a self-consistent eld method in conjunction with a maximum overlap model produces states that are not subject to such mixings. We show that this latter method produces vibronic spectra much more aligned with vertical excitation procedures, such as those computed from a vertical gradient or molecular dynamics trajectory-based approach. For the methylene blue chromophore, we compare vibronic absorption spectra computed with: an adiabatic Hessian approach with linear response theory optimized structures and normal modes, a vertical gradient procedure, the Hessian and normal modes of maximum overlap method optimized structures, and excitation energy time correlation functions generated from a molecular dynamics trajectory. Due to mixing between the bright S1 and dark S2 surfaces near the S1 minimum, computing the adiabatic Hessian with linear response theory time-dependent density functional theory with the B3LYP density functional predicts a large vibronic shoulder for the absorption spectrum that is not present for any of the other methods. Spectral densities are analyzed and we compare the behavior of the key normal mode that in linear response theory strongly couples to the optical excitation while showing S1/ S2 state mixings. Overall, our study provides a note of caution in computing vibronic spectra using the excited state adiabatic Hessian of linear response theory optimized structures and also showcases three alternatives that are not as subject to adiabatic state mixing effects.

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