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Molecular dynamics with restrictions derived from optical spectra

Jakub Kaminský, Jiří ŠEbek, Petr Bouř
2009 Journal of Computational Chemistry  
In this work, the comparison is enhanced by restrictions to molecular dynamics propagations based on the Raman and Raman optical activity spectra.  ...  The information about molecular structure coded in the optical spectra must often be deciphered by complicated computational procedures.  ...  Theory Spectra-Restricted Molecular Dynamics Let us suppose that we can generate an average or instantaneous spectrum S i,k at each time step i of the MD propagation, k is the wavelength.  ... 
doi:10.1002/jcc.21123 pmid:18816457 fatcat:cjcr7pbnu5byzkngrwdmkic5pa

Photophysics of a poly(phenylenevinylene) with alternatingmeta-phenylene andpara-phenylene rings

P. A. Lane, A. J. Cadby, H. Mellor, S. J. Martin, D. G. Lidzey, D. D. C. Bradley, S. M. Lipson, D. F. O'Brien, W. J. Blau
2000 Physical Review B (Condensed Matter)  
The incorporation of alternating meta-phenylene and para-phenylene rings restricts conjugation with respect to poly͑para-phenylenevinylene͒ derivatives.  ...  The reduced symmetry of 1,3-PPV modifies optical selection rules, resulting in strong overlap of the fluorescence spectrum with excited state absorption by charged polarons.  ...  states, which causes a transfer of oscillator strength from allowed to forbidden optical transitions.  ... 
doi:10.1103/physrevb.62.15718 fatcat:mt3awwj35fefdepkqv2wymjk44

Cross-Polarization Detection Enables Fast Measurement of Vibrational Circular Dichroism

Petr Bouř
2009 ChemPhysChem  
[24] We also attempted imposing geometry restrictions derived from optical spectra during molecular dynamics simulations.  ...  [20] To some extent, the "classical" VOA spectra can already be utilized to follow the molecular dynamics.  ... 
doi:10.1002/cphc.200900383 pmid:19514025 fatcat:5c3kphwrkngwdjygh3vbagk4rq

Restriction of the conrotatory motion in photo-induced 6π electrocyclic reaction: formation of the excited state of the closed-ring isomer in the cyclization

Tatsuhiro Nagasaka, Hikaru Sotome, Soichiro Morikawa, Lucas Martinez Uriarte, Michel Sliwa, Tsuyoshi Kawai, Hiroshi Miyasaka
2020 RSC Advances  
Restriction of the molecular geometry opens up a novel pathway in the cyclization reaction of a photochromic dithiazolylarylene derivative.  ...  Decay-associated spectra (DAS) obtained from the global analysis of the transient absorption spectra of DTA(o).  ...  Continuous visible light from a Xenon lamp (LAX-103, Asahi Spectra, 400-700 nm) equipped with a mirror module (LAX-VIS 400-700, Asahi Spectra) was irradiated into the sample solution to keep the concentration  ... 
doi:10.1039/d0ra03523h pmid:35520419 pmcid:PMC9054205 fatcat:fd765gnmejclfojoicpggzcyuq

Evidence of concerted inversion for the photon-induced molecular switching of azobenzene using rotation-free azobenzene derivatives

Ya-Wei Hao, Hai-Yu Wang, You-Ju Huang, Bing-Rong Gao, Qi-Dai Chen, Liang-Bin Li, Hong-Bo Sun
2013 Journal of Materials Chemistry C  
We compared the relaxation dynamics and the time-resolved anisotropic relaxation properties of these two molecules in liquid solution and in bulk film.  ...  The value of anisotropy for Azo-2 remained almost constant at about 0.2 in bulk film but decayed slowly from 0.3 in liquid solution.  ...  To understand the signicantly different relaxation dynamics of these samples, we must look back to the molecular structures of these azobenzene derivatives.  ... 
doi:10.1039/c3tc30879k fatcat:hmnk4djfifh6hizdupknmwny3q

Near-infra-red spectroscopic ages of massive star clusters in M 82

A. Lançon, J. S. Gallagher, M. Mouhcine, L. J. Smith, D. Ladjal, R. de Grijs
2008 Astronomy and Astrophysics  
How do the derived cluster properties compare with previous results from optical studies?  ...  They do not always agree with optical spectroscopic ages. Adding optical data sometimes leads to the rejection of the solar neighbourhood extinction law.  ...  In most cases, the near-IR molecular bands of the models at the ages derived from optical studies are marginally acceptable or too weak.  ... 
doi:10.1051/0004-6361:200809439 fatcat:crnekarzhvdnfah6tegmm3qgni

Page 370 of Astronomy and Astrophysics Vol. 136, Issue 2 [page]

1984 Astronomy and Astrophysics  
We note that the molecular clouds analysed here are known to be closely associated with Gould belt; therefore their kinematical properties may differ from the average properties of local H1 which is only  ...  Dickey et al. (1978) and Melbold et al. (1982) claimed that H1 clouds with low optical depths (t<0.1) have larger velocity dispersions (< V,2)'/?+11kms~') than high optical depth clouds (<V,2>"?  ... 

Light scattering at the liquid to glass transition

M. Fuchs, A. Latz
1991 Journal of Chemical Physics  
The change from liquid to solid-like Brillouin spectra is explained using frequency dependent elasto-optic constants.  ...  The observation of a Rytov Dip in a system of optically isotropic particles is predicted for slow enough viscoelastic relaxation.  ...  Depolarized spectra of molecular liquids are explained with the anisotropy of the molecular polarizability tensor. 6'7 In gases and simple liquids of optically isotropic particles multiple scattering  ... 
doi:10.1063/1.461436 fatcat:eivq3uuaozemhcep53tv3k5bpm

Absolute cross-section measurements in XQQ instruments - The NBS round robin

R.I. Martinez
1988 Journal of Research of the National Bureau of Standards  
Accuracy in Trace Analysis Ar'(Ar,Ar)Ar~ [10] to determine the target thickness [B]L }, followed by ii) the experiment associated with figure 1(a) of [9] .  ...  A dynamically correct instrument is kinetically well behaved if the a derived from eq (1) equals the o-from eq (2) for a charge transfer reaction with a= 1.  ...  Work from this lab [10, [12] [13] [14] when a-derived from eq (1) equals a, from eq (2), (3) , etc. [14] .  ... 
doi:10.6028/jres.093.106 fatcat:aj7ojuafxrgkpeyajnh4tzrhoe

On the limited precision of transfer of molecular optical activity tensors

Shigeki Yamamoto, Petr Bouř
2011 Collection of Czechoslovak Chemical Communications  
Transfer of molecular property tensors (force field, dipole derivatives, polarizabilities, etc.) from smaller fragments to bigger molecules is powerful tool to calculate molecular vibrational spectra.  ...  In the second part of the study, tensor derivatives are transferred from smaller fragments to model valinomycin and insulin molecules, and the resultant tensor derivatives and ROA spectra compared to benchmark  ...  This study was performed with the support from the Academy of Sciences (M200550902), the KONTAKT II MSMT program (LH11033), Czech Science Foundation (P208/11/0105), Luna, Metacentrum and University of  ... 
doi:10.1135/cccc2011018 fatcat:yoxqshx7njgujbiodyvwvmcghi

Segmental dynamics in poly(methyl acrylate) on silica: Molecular-mass effects

Burak Metin, Frank D. Blum
2006 Journal of Chemical Physics  
The effect of molecular mass on the segmental dynamics of poly͑methyl acrylate͒ ͑PMA͒ adsorbed on silica was studied using deuterium quadrupole-echo nuclear magnetic resonance ͑NMR͒ and modulated differential  ...  This heterogeneity was consistent with a motional gradient with more-mobile segments near the polymer-air interface and the less-mobile species near the polymer-silica interface.  ...  FIG. 6 . 6 MDSC thermograms ͑derivative mode͒ for bulk and adsorbed PMA with different molecular masses. FIG. 8 . 8 The Boltzmann-corrected intensity curves obtained from the NMR experiments.  ... 
doi:10.1063/1.2219739 pmid:16942241 fatcat:k6sj7smzxffnfmgkuydt6nvkzm

Dynamical Modelling of AGB Star Atmospheres

Susanne Höfner
1999 Symposium - International astronomical union  
So far, hydrostatic model atmospheres have been used in most cases to analyse photospheric spectra, neglecting the effects of dynamics.  ...  Time-dependent dynamics is an important ingredient for understanding the atmospheres of pulsating AGB stars.  ...  In contrast, Bessell et al. (1996) and Scholz (1992) based their investigations on photospheric models calculated with a variable inner boundary derived from the dynamic models of Wood (1990) .  ... 
doi:10.1017/s0074180900203021 fatcat:zhtteebb2bfp7au3a2efqxxiwe

Opacity broadening and interpretation of suprathermal CO linewidths: Macroscopic turbulence and tangled molecular clouds

A. Hacar, J. Alves, A. Burkert, P. Goldsmith
2016 Astronomy and Astrophysics  
This highly discretized structure of the molecular gas traced in CO suggest that the gas dynamics inside molecular clouds could be better described by the properties of a fully-resolved macroscopic turbulence  ...  Combined with the presence of multiple components detected in our C^18O spectra, these opacity effects seem to be also responsible of the highly supersonic linewidths ( M>8-10) detected in the broadest  ...  A.H. gratefully acknowledges support from Ewine van Dishoeck, John Tobin, and Magnus Persson during his stay at the Leiden Observatory.  ... 
doi:10.1051/0004-6361/201527319 fatcat:xwaw6ja5mbetvamphs5brbhdze

Vibrational circular dichroism of tetraphenylporphyrin in peptide complexes? A computational study

Petr Bou?, Kamil Z�ruba, Marie Urbanov�, Vladim�r Setni?ka, Pavel Mat?jka, Zden?k Fiedler, Vladim�r Kr�l, Karel Volka
2000 Chirality  
In order to estimate whether induced optical activity in chiral complexes interferes with the signal of peptide vibrations, the vibrational circular dichroism (VCD) spectra of TPP were simulated.  ...  No significant contribution to VCD signal from the TPP residue was found in experimental spectra.  ...  This is important for the interpretation of the vibrational optical activity, which is based primarily on quantum-chemical modeling. 5 Many spectroscopic properties can be derived from the symmetry rules  ... 
doi:10.1002/(sici)1520-636x(2000)12:4<191::aid-chir5>;2-w pmid:10790189 fatcat:w2por6yykrdcxaehi37tgcyk2i

Page 255 of Astronomy and Astrophysics Vol. 259, Issue 1 [page]

1992 Astronomy and Astrophysics  
outflow which is perfectly aligned with the optical jet HH 46/47 and originating from the same source.  ...  The derived values for outflow mass and mechanical luminosity are at the lower end of the range known from compiled lists of molecular outflows (e.g. Lada 1985).  ... 
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