Theoretical investigation of the nonlinear optical properties of oligomers of polythienylenemethylidene, a low band‐gap material

Autor:	J.L. Brédas, David Beljonne, C. Adant
Rok vydání:	1994
Předmět:	chemistry.chemical_compound Dipole Nonlinear system chemistry Band gap Polarizability Excited state Thiophene General Physics and Astronomy Physical and Theoretical Chemistry Atomic physics Configuration interaction Excitation
Zdroj:	The Journal of Chemical Physics. 101:8048-8054
ISSN:	1089-7690 0021-9606
DOI:	10.1063/1.468231
Popis:	We present a theoretical investigation by the sum‐over‐states formalism of the static first‐ and third‐order polarizabilities of thienylenemethylidene oligomers; following the incorporation of a single conjugated carbon between the rings, these compounds present a partially quinoid geometry. We use a multireference determinant single–double configuration interaction approach to calculate excited‐state energies, state dipole moments, and transition dipole moments which are introduced in the sum‐over‐states expressions. All the results are discussed in comparison to those obtained in thiophene oligomers of similar sizes; they indicate that the third‐order polarizabilities are smaller for the methine‐bridged compounds than for the corresponding thiophene oligomers. This feature is rationalized by analyzing the main optical (virtual excitation) channels that contribute to the nonlinear response.
Databáze:	OpenAIRE
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