scholarly journals Multidimensional characterization of the conical intersection seam in the normal mode space

2020 ◽  
Vol 11 (26) ◽  
pp. 6856-6861
Author(s):  
Heesung Lee ◽  
So-Yeon Kim ◽  
Sang Kyu Kim
Keyword(s):  
Normal Mode ◽  
Transition Probability ◽  
Conical Intersection ◽  
Nonadiabatic Transition ◽  
Mode Space ◽  
Nonadiabatic Transition Probability

Multidimensional conical intersection seam has been characterized by utilizing the dynamic resonances in the nonadiabatic transition probability experimentally observed in the predissociation of thioanisole isotopomers.

scholarly journals Rapid Characterization of Allosteric Networks with Ensemble Normal Mode Analysis

2016 ◽  
Vol 120 (33) ◽  
pp. 8276-8288 ◽  
Author(s):  
Xin-Qiu Yao ◽  
Lars Skjærven ◽  
Barry J. Grant
Keyword(s):  
Normal Mode ◽  
Normal Mode Analysis ◽  
Mode Analysis ◽  
Rapid Characterization

Synthesis and Characterization of a Fluorescent Dianthraceno­indacene

Synlett ◽  
2018 ◽  
Vol 29 (19) ◽  
pp. 2562-2566 ◽  
Author(s):  
Michael Haley ◽  
Conerd Frederickson ◽  
Joshua Barker ◽  
Justin Dressler ◽  
Zheng Zhou ◽  
...  
Keyword(s):  
Neutral Molecule ◽  
Conical Intersection ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Irreversible Reduction ◽  
Inside Out

A freely soluble dianthracenoindacene derivative has been synthesized using an ‘inside-out’ Friedel–Crafts alkylation method and is the first fluorescent diacenoindacene reported. Linear fusion of the anthracenes is confirmed by X-ray diffraction studies on the neutral molecule as well as its dianion. Based on predictions from our previous studies, this is also the least antiaromatic diacenoindacene derivative yet to be prepared, which is reflected in its highly negative and irreversible reduction. With its paratropicity essentially eliminated, we posit that the molecule is no longer deactivated by a conical intersection, typical of antiaromatic molecules, and therefore fluorescence is restored. This follows the trend shown in the related dianthracenopentalenes, with the reappearance of fluorescence when the outer acene groups are extended to linearly-fused anthracene moieties.

Characterization of convergence rates for the approximation of the stationary distribution of infinite monotone stochastic matrices

1996 ◽  
Vol 33 (04) ◽  
pp. 974-985 ◽  
Author(s):  
F. Simonot ◽  
Y. Q. Song
Keyword(s):  
Convergence Rate ◽  
Generating Function ◽  
Convergence Rates ◽  
Transition Probability ◽  
Stochastic Matrix ◽  
Input Sequence ◽  
Transition Probability Matrix ◽  
Stochastic Matrices ◽  
Preceding Result

Let P be an infinite irreducible stochastic matrix, recurrent positive and stochastically monotone and Pn be any n × n stochastic matrix with Pn ≧ Tn , where Tn denotes the n × n northwest corner truncation of P. These assumptions imply the existence of limit distributions π and π n for P and Pn respectively. We show that if the Markov chain with transition probability matrix P meets the further condition of geometric recurrence then the exact convergence rate of π n to π can be expressed in terms of the radius of convergence of the generating function of π. As an application of the preceding result, we deal with the random walk on a half line and prove that the assumption of geometric recurrence can be relaxed. We also show that if the i.i.d. input sequence (A(m)) is such that we can find a real number r 0 > 1 with , then the exact convergence rate of π n to π is characterized by r 0. Moreover, when the generating function of A is not defined for |z| > 1, we derive an upper bound for the distance between π n and π based on the moments of A.

Stochastic population processes in the theory of radiative transfer

1970 ◽  
Vol 7 (02) ◽  
pp. 272-290
Author(s):  
P. J. Brockwell
Keyword(s):  
Radiative Transfer ◽  
Transition Probability ◽  
Collision Integral ◽  
Time Interval ◽  
Reciprocity Principle ◽  
Initial State ◽  
First Passage ◽  
Generating Functional ◽  
Generalized State

Summary Starting from a characterization of radiative transfer in terms of a collision rate λ and a single-collision transition probability Ψ, we study the distribution of the generalized state ζ(t) of a radiation particle at time t conditional on a specified initial state at time t = 0. The generalized state is a vector consisting of the state ω(t) at time t and the states ω 1, ω 2, …, ω n of the particle immediately after the collisions it experiences in the time interval (0, t]. The variable ζ(t) takes values in a population space and can be studied conveniently with the aid of a certain generating functional G. The first-collision integral equation and the backward integro-differential equation for G are derived. Simultaneous consideration of the first-collision and last-collision equations lead to a generalized reciprocity principle for G. First-passage problems are also considered. Finally a number of illustrative examples are given.

Characterization of unstable rock slopes using ambient vibration analysis

2020 ◽  
Author(s):  
Donat Fäh ◽  
Mauro Häusler ◽  
Franziska Glueer ◽  
Jan Burjanek ◽  
Ulrike Kleinbrod
Keyword(s):  
Seismic Response ◽  
Normal Mode ◽  
Wave Velocity ◽  
Ambient Vibration ◽  
Mode Analysis ◽  
Permafrost Degradation ◽  
Rock Slopes ◽  
Spectral Ratios ◽  
S Wave

<p>Earthquake-induced landslides can have serious social impacts, causing many casualties and significant damage to infrastructure. They are the most destructive secondary hazards related to earthquakes. The impact of strong seismic events is not limited just to triggering of catastrophic slope failures, it also involves weakening of intact rock masses and reactivation of dormant slides. Hazard mitigation of potentially catastrophic landslides requires a thorough understanding of the mechanisms driving slope movements and seismic response.</p><p>We present an overview of the investigations on more than 25 instabilities. The results show that ambient vibration measurements allow for a rapid and objective characterization of potential slope instabilities. It is possible to distinguish unstable from stable areas, to identify slope eigen-frequencies, local amplification levels due to weak excitation, local deformation directions and properties of the internal slope structure. The ambient vibration techniques include single-station H/V ratios and polarization analyses, site-to-reference spectral ratios, array methods to identify surface-wave dispersion curves, and/or normal mode analysis using enhanced frequency domain decomposition. We analyse the seismic response of the rock slopes in different frequency bands together with its spatial and azimuthal variability, which is a fingerprint of the slope’s internal structure at different scales (tenth of meters to hundred meters). Normal mode behaviour is typically observed in structures with distinct sub-volumes, where the wave field at the resonance frequencies is oriented perpendicular to the deep persistent fractures. These structures show maximum amplification at their resonance frequency. Normal mode behaviour is also observed for rock towers, similar to what can be observed for buildings. In contrast, a highly fractured rock mass without dominant cracks is characterized by an S-wave velocity gradient with shear-wave velocity being significantly reduced close to the surface. Generally, normal modes do not develop, but surface waves propagate in such structures, which can be used for the determination of the S-wave profile. This is typical for large deep seated landslides with a layered structure. Without strong S-wave velocity contrast at depth, H/V spectral ratios show no clear peak and are not conclusive to characterize structures with highly fractured material. However, frequency-dependent ground-motion amplification from standard spectral ratios is directly related to the S-wave velocity profile and damping. Therefore, wave amplification can be a measure for the disintegration of the rock.</p><p>Repeated measurements on slopes allow for the detection of possible changes in their properties. Semi-permanent installations on instabilities of interest allow for a continuous assessment of the dynamic response in order to understand variations due to weather conditions and potential long-term changes. This includes the measurement of site-amplification during earthquakes derived from empirical spectral modelling. When measuring in the same season and weather condition, the seismic response of rock instabilities in general remains unchanged over years, as long a no external trigger affects the instability, including a strong earthquake, partial failure of the slope or permafrost degradation.</p>

Characterization of Protein Conformational States by Normal-Mode Frequencies

2007 ◽  
Vol 129 (37) ◽  
pp. 11394-11401 ◽  
Author(s):  
Benjamin A. Hall ◽  
Samantha L. Kaye ◽  
Andy Pang ◽  
Rafael Perera ◽  
Philip C. Biggin
Keyword(s):  
Normal Mode ◽  
Conformational States
Sign in / Sign up

Export Citation Format

Share Document