Vibronic structure has been resolved in two-photon photoemission (2PPE) from the highest occupied molecular orbital (HOMO)-derived level of lead phthalocyanine film formed on graphite. The 2PPE from the HOMO-derived level was enhanced by the resonance with the third lowest unoccupied molecular orbital (LUMO+2) -derived level. At photon energies below and well above the resonance, the intensity of the vibronic structure was similar to that of one-photon photoemission. On the other hand, the vibronic structure was significantly weak at photon energies slightly above (<0.4 eV) the resonance. The decrease in the vibronic structure was attributed to the nuclear motion of molecule in the intermediate state associated with LUMO+2.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 2009 9月 30|
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