| Autor: |
Baba, Masaaki, Saitoh, Motohisa, Taguma, Kunio, Shinohara, Keisuke, Yoshida, Kazuto, Semba, Yosuke, Kasahara, Shunji, Nakayama, Naofumi, Goto, Hitoshi, Ishimoto, Takayoshi, Nagashima, Umpei |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 4/7/2009, Vol. 130 Issue 13, p134315, 9p, 2 Diagrams, 5 Charts, 6 Graphs |
| Abstrakt: |
Rotationally resolved ultrahigh-resolution spectra of the S1 1B2u←S0 1Ag transition of anthracene-h10 and anthracene-d10 have been observed using a single-mode UV laser and a collimated supersonic jet. We have determined rotational constants of the zero-vibrational levels of the S0 and S1 states by analyzing the precisely calibrated transition wavenumbers of rotational lines. We measured Zeeman splitting of each rotational line in the external magnetic field, of which the magnitude was small and strongly dependent on the rotational quantum numbers. We have shown that the magnetic moment in the S1 1B2u state arises from J-L coupling with the S2 1B3u state and that mixing with the triplet state is negligibly small. We concluded that the main radiationless transition in the S1 state of anthracene is not intersystem crossing to the triplet state but internal conversion to the ground state. We also examined methods of ab initio theoretical calculation to determine which method most closely yielded the same values of rotational constants as the experimentally obtained ones. Moller–Plesset second-order perturbation method with a 6-31G(d,p) basis set yielded approximately the same values for the S0 1Ag state with an error of less than 0.04%. Geometrical structure in the S0 1Ag state of the isolated anthracene molecule has been accurately determined by this calculation. However, configurational-interaction with single excitations, time-dependent Hartree–Fock, and time-dependent density-function-theory methods did not yield satisfactory results for the excitation energy of the S1 1B2u state. Symmetry-adapted-cluster configuration-interaction calculation was sufficiently good for the excitation energy and rotational constants. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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