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Titolo:
Ultrafast dichroism spectroscopy of anthracene in solution. 1. Inertial versus diffusive rotation in benzyl alcohol
Autore:
Zhang, YH; Sluch, MI; Somoza, MM; Berg, MA;
Indirizzi:
Univ S Carolina, Dept Chem & Biochem, Columbia, SC 29208 USA Univ S Carolina Columbia SC USA 29208 m & Biochem, Columbia, SC 29208 USA
Titolo Testata:
JOURNAL OF CHEMICAL PHYSICS
fascicolo: 9, volume: 115, anno: 2001,
pagine: 4212 - 4222
SICI:
0021-9606(20010901)115:9<4212:UDSOAI>2.0.ZU;2-H
Fonte:
ISI
Lingua:
ENG
Soggetto:
VISCOELASTIC CONTINUUM MODEL; MOLECULAR-DYNAMICS SIMULATIONS; FEMTOSECOND SOLVATION DYNAMICS; AXIALLY-SYMMETRICAL SOLUTES; MULTIPLE TIME SCALES; NONPOLAR SOLVATION; LIGHT-SCATTERING; FLUORESCENCE ANISOTROPY; MICROSCOPIC FRICTION; SUPERCOOLED LIQUIDS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
66
Recensione:
Indirizzi per estratti:
Indirizzo: Berg, MA Univ S Carolina, Dept Chem & Biochem, Columbia, SC 29208 USA UnivS Carolina Columbia SC USA 29208 em, Columbia, SC 29208 USA
Citazione:
Y.H. Zhang et al., "Ultrafast dichroism spectroscopy of anthracene in solution. 1. Inertial versus diffusive rotation in benzyl alcohol", J CHEM PHYS, 115(9), 2001, pp. 4212-4222

Abstract

Dichroism experiments with 150 fs time resolution on anthracene in benzyl alcohol are presented as a function of viscosity from 14.4 cP (274 K) to 2.7 cP (329 K). These measurements test a qualitative prediction of the viscoelastic picture of liquid dynamics, specifically that earlier "inertial" dynamics have a viscosity independent rate, whereas later "diffusive" dynamics have a rate directly proportional to viscosity. This paper focuses on twocomponents of the dichroism decay that are assigned to rotational motion. A third component is assigned to electronic-state solvation and is analyzedin a companion paper [J. Chem. Phys. 115, 4231 (2001)]. The longest component is due to rotational diffusion and is very well described by a hydrodynamic model with slip boundary conditions. A fast decay component in the subpicosecond region is found and shown to have a viscosity-independent rate. It is assigned to inertial rotation by comparison to the computer simulations of Jas et al. [J. Chem. Phys. 107, 8800 (1997)]. Inertial rotation extends out to at least 1 ps, longer than the range commonly assumed for inertial dynamics. Over much of this range, the inertial rotation is not free-rotor-like, but is strongly modified by interaction with the solvent. The inertial rotation also accounts for the "missing" anisotropy found when the rotational diffusion fits are extrapolated to zero time. (C) 2001 American Institute of Physics.

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Documento generato il 30/11/20 alle ore 03:11:15