Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Effects of matrix temperature and rigidity on the electronic properties ofsolvatochromic molecules: Electroabsorption of coumarin 153
Autore:
Chowdhury, A; Locknar, SA; Premvardhan, LL; 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 A
fascicolo: 48, volume: 103, anno: 1999,
pagine: 9614 - 9625
SICI:
1089-5639(199912)103:48<9614:EOMTAR>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
STATE DIPOLE-MOMENTS; POLAR SOLVATION DYNAMICS; DONOR-ACCEPTOR POLYENES; BOND-LENGTH ALTERNATION; STARK SPECTROSCOPY; STOKES SHIFT; RELAXATION; SOLVENT; ABSORPTION; SIMULATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
63
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:
A. Chowdhury et al., "Effects of matrix temperature and rigidity on the electronic properties ofsolvatochromic molecules: Electroabsorption of coumarin 153", J PHYS CH A, 103(48), 1999, pp. 9614-9625

Abstract

Using Stark effect (electroabsorption) spectroscopy to study the well-known solvatochromic probe molecule coumarin 153 (C153) in a variety of polymermatrices and organic glasses, we have found that the average change in polarizability (<(Delta<(alpha)double under bar>)over bar>) that we measure depends critically on the rigidity of the matrix used. In rigid polymer and frozen organic glass matrices, the measured values <(Delta<(alpha)double under bar>)over bar> are between 4 and 60 Angstrom(3). The smaller values in this range are similar to those obtained via semiempirical and ab initio calculations, In contrast, measurements made on polymer matrices that are above their glass-transition temperature or those containing trapped solvent are more than an ol-der of magnitude higher. We postulate that large values of acr result from field-induced orientation of the C153 molecule and/or thedipoles of the surrounding matrix in matrices that are not fully rigid. The absolute value of the change in dipole moment between the ground and excited states (\Delta<(mu)under bar>\) of C153 measured here:ranges from 4.4 to 7.0 D, depending on the polarity and the rigidity of the environment. In addition, an apparent local enhancement of the polarity of the cavity containing C153 is observed in both the solvent and polymer glass matrices, as inferred by the absorption maximum of C153 in these environments.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/12/20 alle ore 23:41:18