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Titolo:
A theoretical study of second hyperpolarizabilities for donor-acceptor-donor molecules
Autore:
Yang, ML; Jiang, YS;
Indirizzi:
Nanjing Univ, Dept Chem, Nanjing 210093, Peoples R China Nanjing Univ Nanjing Peoples R China 210093 jing 210093, Peoples R China
Titolo Testata:
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
fascicolo: 2, volume: 3, anno: 2001,
pagine: 167 - 171
SICI:
1463-9076(2001)3:2<167:ATSOSH>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
NONLINEAR-OPTICAL-PROPERTIES; BOND-LENGTH ALTERNATION; PUSH-PULL MOLECULES; INTRAMOLECULAR CHARGE-TRANSFER; CONJUGATED ORGANIC-MOLECULES; HYPER-RAYLEIGH SCATTERING; SQUARAINE DYES; POLARIZABILITIES; MODEL; POLYENES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
54
Recensione:
Indirizzi per estratti:
Indirizzo: Yang, ML Nanjing Univ, Dept Chem, Nanjing 210093, Peoples R China Nanjing Univ Nanjing Peoples R China 210093 93, Peoples R China
Citazione:
M.L. Yang e Y.S. Jiang, "A theoretical study of second hyperpolarizabilities for donor-acceptor-donor molecules", PHYS CHEM P, 3(2), 2001, pp. 167-171

Abstract

The linear polarizabilities alpha and second hyperpolarizabilities gamma of molecules with donor-acceptor-donor (D-A-D) motifs were calculated by a semi-empirical molecular orbital method through the finite-field approach. The bond-length alternation (BLA) parameter was used to consider the structure-property relationship for this class of molecule. By tuning the molecular ground-state geometries with the applied electric field, the dependence of the longitudinal components, alpha (xx) and gamma (xxxx), on the BLA parameter is obtained, differing from those for push-pull chromophores. With the reduction of BLA, the value of alpha (xx) increases monotonously, while gamma (xxxx) is firstly positive and increases, reaches a maximum, then decreases and crosses through zero, ultimately approaching a negative maximum. The extension of the conjugation paths connecting the acceptor and the two donors leads to a rapid increase in alpha (xx) and gamma (xxxx) values for short oligomers, accompanied by a sign reversion (from positive to negative) in gamma (xxxx) for some oligomers with highly polarized structures. A strategy for designing and synthesizing D-A-D-like molecules with large positive or negative third-order optical non-linearities is suggested based on the calculated results.

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Documento generato il 30/11/20 alle ore 17:04:30