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Photoisomerization dynamics of trans–trans, cis–trans, and cis–cis diphenylbutadiene from broadband transient absorption spectroscopy and calculationsстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 29 июля 2020 г.
- Авторы: Krohn O.A., Quick M., Sudarkova S.M., Ioffe I.N., Richter C., Kovalenko S.A.
- Журнал: Journal of Chemical Physics
- Том: 152
- Номер: 22
- Год издания: 2020
- Издательство: AIP Publishing
- Местоположение издательства: United States
- Первая страница: 224305
- DOI: 10.1063/5.0007241
- Аннотация: The photoisomerization path and dynamics of trans–trans (ttD), cis–trans (ctD), and cis–cis (ccD) 1,4-diphenyl-1,3-butadiene (DPB) in solution are studied with broadband transient absorption (TA) spectroscopy and quantum chemical calculations. For ttD in n-hexane, 2-photon-excited TA spectra indicate that the 2Ag state is located above 1-photon allowed 1Bu (S1) by ∼1000 cm−1. Following S0 → S1 optical excitation, the isomerization occurs via torsion about a butadiene double bond to perpendicular molecular configuration P. The P-state is detected in ccD with an excited-state absorption band at 390 nm. This P-band develops during S1 → P half-torsion with time of 0.15 ps, followed further by P → S0 half-torsion and simultaneous decay with 1.6 ps in acetonitrile and 5 ps in n-hexane. In addition, two oscillation cycles between P and S1 population are observed before equilibration in n-hexane. For ctD, an indication of rising and decaying P is found in acetonitrile. The vast majority of ctD species photoisomerizes to ttD and not to ccD, in agreement a with calculated low torsional barrier about the cis double bond and high barrier about the trans double bond. Photoisomerization yield Y and time τi depend drastically on the solvent polarity. Thus, in n-hexane, the isomerization ttD → ctD has yield Ytt,ct = 0.1 and time τi = 829 ps, while in acetonitrile, Ytt,ct = 0.4 and τi = 27 ps. The 30-fold acceleration of the isomerization in acetonitrile clearly reflects a highly polar character of P, consistent with a dipole moment μP > 9.6 D. The results for DPB are discussed in comparison to stilbene.
- Добавил в систему: Сударькова Светлана Михайловна