Dynamic Fields and Response Properties

2020 ◽  
pp. 473-554
Author(s):  
Jochen Autschbach
Keyword(s):  
Absorption Coefficient ◽  
Linear Response ◽  
Optical Rotation ◽  
Polarized Light ◽  
Linear Response Theory ◽  
Time Dependent ◽  
Electronic Transitions ◽  
Orbital Theory ◽  
Response Properties ◽  
Set Up

It is shown how electronic transitions can be induced by the interaction with an electromagnetic wave of a suitable frequency. The rate of a transition between two electronic states induced by a time-dependent field is derived. The transition rate expression is used to calculate the absorption coefficient due to electronic transitions. The differential absorption coefficient for left and right circular polarized light is specific to chiral molecules and has different signs for a pair of enantiomers. The discussion then shifts to general functions describing the response of an atom or molecule to an external. The ideas developed thus far are then applied to the dynamic polarizability, molecular linear response functions in general, and the optical rotation. Linear response theory is set up within time-dependent molecular orbital theory. The Chapter concludes with a discussion of non-linear response properties and two-photon absorption.

Hydrodynamic mode of a magnetic heat energy. Application of the linear response theory to a simple magnetic system

1970 ◽  
Vol 48 (3) ◽  
pp. 283-296
Author(s):  
K. C. Lee
Keyword(s):  
Linear Response ◽  
Magnetic System ◽  
Linear Response Theory ◽  
Thermodynamic Quantities ◽  
Response Theory ◽  
Hydrodynamic Mode ◽  
One Dimensional ◽  
Thermal Disturbance ◽  
Set Up ◽  
The One

The hydrodynamic mode of heat in a simple magnetic system has been studied using linear response theory. The initial thermal disturbance has been set up by mechanical means. Expressions for local thermodynamic quantities analogous to the fluid system have been obtained. These results are used for the derivation of the hydrodynamic equation for the one-dimensional spin-[Formula: see text]X–Y model for which exact equilibrium correlation functions are calculable. The local temperature satisfies the wave equation indicating the existence of second sound in this model.

Atomic transport via point defects in crystals V. Equivalence of kinetic and linear response theories

1987 ◽  
Vol 413 (1845) ◽  
pp. 429-441 ◽  
Keyword(s):  
Kinetic Theory ◽  
Point Defects ◽  
Linear Response ◽  
Transport Coefficients ◽  
Linear Response Theory ◽  
Time Dependent ◽  
Defects In Crystals ◽  
Response Functions ◽  
Atomic Transport ◽  
Solute Atoms

Earlier papers in this series have presented a general formulation of the kinetic theory of isothermal atomic transport via point defects. This has been used to derive expressions for the macroscopic transport coefficients and to analyse the response to time-dependent fields in terms of parameters characterizing the defects and their interaction with solute atoms, etc. In this paper it is shown that these transport coefficients and response functions are invariant with respect to a class of transformations of the quantities representing the defect displacements in all the transitions considered. In this way the exact equivalence of these results of kinetic theory to corresponding results of the linear response theory of Allnatt and Okamura is demonstrated.

scholarly journals Solvation dynamics in polar solvents and imidazolium ionic liquids: failure of linear response approximations

2018 ◽  
Vol 20 (7) ◽  
pp. 5246-5255 ◽  
Author(s):  
Esther Heid ◽  
Christian Schröder
Keyword(s):  
Ionic Liquids ◽  
Linear Response ◽  
Large Scale ◽  
Linear Response Theory ◽  
Time Dependent ◽  
Solvation Dynamics ◽  
Polar Solvents ◽  
Imidazolium Ionic Liquids ◽  
Fluorescence Measurements ◽  
Solvent Systems

Large scale computer simulations of different fluorophore-solvent systems reveal when and why linear response theory applies to time-dependent fluorescence measurements.

scholarly journals Intramolecular Communication and Allosteric Sites in Enzymes Unraveled by Time-Dependent Linear Response Theory

2019 ◽  
Author(s):  
Bang-Chieh Huang ◽  
Chi-Hong Chang-Chein ◽  
Lee-Wei Yang
Keyword(s):  
Equilibrium State ◽  
Linear Response ◽  
Signal Propagation ◽  
Linear Response Theory ◽  
Time Dependent ◽  
Response Theory ◽  
Functional Sites ◽  
Allosteric Sites ◽  
Intramolecular Communication ◽  
Non Equilibrium

ABSTRACTIt has been an established idea in recent years that protein is a physiochemically connected network. Allostery, understood in this new context, is a manifestation of residue communicating between remote sites in this network, and hence a rising interest to identify functionally relevant communication pathways and the frequent communicators within. Previous studies rationalized the coupling between functional sites and experimentally observed allosteric sites by theoretically discovered high positional/velocity/thermal correlations between these sites. However, for one to systematically discover previously unobserved allosteric sites in any receptor/enzyme providing the position of functional (orthosteric) sites, these high correlations may not be able to identify remote allosteric sites because of a number of false-positives while many of those are located in proximity to the functional site. Also, whether allosteric sites should be found in equilibrium or non-equilibrium state of a protein to be more biologically relevant is not clear, neither is the directionality preference of aforementioned propagating signals. In this study, we devised a time-dependent linear response theory (td-LRT) integrating intrinsic protein dynamics and perturbation forces that excite protein’s temporary reconfiguration at the non-equilibrium state, to describe atom-specific time responses as the propagating mechanical signals and discover that the most frequent remote communicators can be important allosteric sites, mutation of which would deteriorate the hydride transfer rate in DHFR by 2 to 3 orders. The preferred directionality of the signal propagation can be inferred from the asymmetric connection matrix (CM), where the coupling strength between a pair of residues is suggested by their communication score (CS) in the CM, which is found consistent with experimentally characterized nonadditivity of double mutants. Also, the intramolecular communication centers (ICCs), having high CSs, are found evolutionarily conserved, suggesting their biological importance.

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