Vibrational Structure in the Electronic Spectra of C60 and Fullerene Derivatives as Studied by Time-Dependent Density Functional Theory
| Autor: | Sergey I. Troyanov, A. N. Starukhin, N. S. Ovchinnikova, Alexey A. Popov, B. S. Razbirin, Vitaly I. Korepanov, Vladimir M. Senyavin, Marina A. Yurovskaya |
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| Rok vydání: | 2007 |
| Předmět: | |
| Zdroj: | ECS Transactions. 2:121-132 |
| ISSN: | 1938-6737 1938-5862 |
| Popis: | Absorption and fluorescence spectra of fullerenes and their derivatives in the visible range often exhibit complex vibrational structure (1). Vibronic transitions may be induced by Herzberg-Teller (H-T) mechanism for the dipole-forbidden electronic transitions or by Frank-Condon (F-C) mechanism for dipole-allowed transitions. For degenerated excited states, Jahn-Teller (J-T) activity is also expected. Reliable interpretation of the electronic spectra inevitably requires theoretical modeling of the vibrational structure, but for such polyatomic systems as fullerenes this problem represents a challenge from computational point of view. As a result, only few examples are presented in the literature, all based on the use of semiempirical quantum chemical procedures to describe excited states at the level of singles configuration interaction (CNDO/S, INDO/S) (1,2). Though quite successful in modeling fluorescence spectra of C60, in general these methods are not sufficiently reliable, absolute errors in peak positions reaching 0.5 eV or more with scatter of ±0.5 eV, while oscillator strengths appear even less reliable (3). Unfortunately, application of the more robust methods for modeling of electronic spectra and especially vibronic structure of fullerenes was virtually prohibited in the view of the large size of the molecules and enormous computational demands. However, development of the computational equipment and implementation of new computational algorithms make these problems less prohibitive now, and in this work we explore the possibility of modeling vibrational structure of absorption and emission spectra of fullerene C60 and its derivatives with the use of timedependent density functional theory (TDDFT). |
| Databáze: | OpenAIRE |
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