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Titolo:
Matrix and temperature effects on the electronic properties of conjugated molecules: An electroabsorption study of all-trans-retinal
Autore:
Locknar, SA; Chowdhury, A; Peteanu, LA;
Indirizzi:
Carnegie Mellon Univ, Dept Chem, Pittsburgh, PA 15213 USA Carnegie Mellon Univ Pittsburgh PA USA 15213 em, Pittsburgh, PA 15213 USA
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 24, volume: 104, anno: 2000,
pagine: 5816 - 5824
SICI:
1520-6106(20000622)104:24<5816:MATEOT>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
EXCITED-STATE POLARIZABILITIES; NONLINEAR-OPTICAL-PROPERTIES; STARK-EFFECT SPECTROSCOPY; DIPOLE-MOMENTS; PHOTOSYNTHETIC ANTENNA; SUPERCOOLED LIQUIDS; DIMERIC MOLECULES; BACTERIORHODOPSIN; POLYENES; MODEL;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
69
Recensione:
Indirizzi per estratti:
Indirizzo: Peteanu, LA Carnegie Mellon Univ, Dept Chem, 4400 5th Ave, Pittsburgh, PA 15213 USA Carnegie Mellon Univ 4400 5th Ave Pittsburgh PA USA 15213 USA
Citazione:
S.A. Locknar et al., "Matrix and temperature effects on the electronic properties of conjugated molecules: An electroabsorption study of all-trans-retinal", J PHYS CH B, 104(24), 2000, pp. 5816-5824

Abstract

Using Stark effect (electroabsorption) spectroscopy to study all-trans-retinal (ATR) in a variety of polymer matrices and organic glasses, we have found that the average change in polarizability upon excitation (<(Delta alpha)over bar>) that we measure is highly dependent on the rigidity of the matrix used. In rigid polymer and organic glass matrices, the measured values of <(Delta alpha)over bar> are in the range of 20-50 Angstrom(3) and those calculated using semiempirical methods are in the range of 60-85 Angstrom(3). I, contrast, <(Delta alpha)over bar>'s that are up to an order of magnitude higher are measured when the ATR is entrained in nonrigid polymer matrices such as those that are above their glass-transition temperature, or those containing trapped solvent. We have postulated that large values of <(Delta alpha)over bar> may be the result of field-induced orientation of ATR within polymer matrices that are not fully rigid. The /Delta mu/ of ATR ranges from roughly 3 to 11 D, depending on the polarity and the rigidity of the environment. In addition, vibrational structure is apparent in the electroabsorption spectra of ATR in methylcyclohexane and methyltetrahydrofuran glasses at 77 K that is assigned to a progression of the C=C stretch.

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Documento generato il 05/12/20 alle ore 23:18:18