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Why do disilanes fail to fluoresce?
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SYSNO ASEP 0376088 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Why do disilanes fail to fluoresce? Author(s) MacLeod, M. K. (US)
Michl, Josef (UOCHB-X) RID, ORCIDNumber of authors 2 Source Title Collection of Czechoslovak Chemical Communications. - : Ústav organické chemie a biochemie AV ČR, v. v. i. - ISSN 0010-0765
Roč. 76, č. 12 (2011), s. 2085-2116Number of pages 32 s. Language eng - English Country CZ - Czech Republic Keywords excited states ; relaxed excited state ; excited state potential energy minima ; molecular orbitals Subject RIV CF - Physical ; Theoretical Chemistry CEZ AV0Z40550506 - UOCHB-X (2005-2011) UT WOS 000299816100040 DOI 10.1135/cccc2011179 Annotation In contrast to longer peralkylated oligosilanes, many of which fluoresce efficiently, disilanes and trisilanes exhibit no detectable fluorescence even at low temperatures. This is especially striking in the case of disilanes, whose S-1-S-0 transition is quite strongly allowed, and which must have very efficient electronic excited state deactivation mechanisms. To identify them, we examine the lowest excited singlet state potential energy surface S-1 of Si2Me6 with TDDFT (B3LYP/TZVP, PBE0/TZVP and BHLYP/TZVP) and ab initio (RICC2/TZVP and RIADC(2)/TZVP) methods and identify several shallow minima and nearby funnels. Relaxed excited state structures show strong valence rehybridization relative to the ground state, allowing optimal accomodation of the simultaneous presence of a negative and a positive charge in their Lewis structures. Efficient decay pathways and relations to longer oligosilanes are discussed. Workplace Institute of Organic Chemistry and Biochemistry Contact asep@uochb.cas.cz ; Kateřina Šperková, Tel.: 232 002 584 ; Jana Procházková, Tel.: 220 183 418 Year of Publishing 2012
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