Coherent molecular vibrational dynamics studied by a 10-fs laser pulse in comparison for selective and nonselective excitation

Various selective excitation methods for molecular vibrations have been developed based on the characteristics of the applied lasers. In the present work, we coherently and selectively excited molecular vibrations up to 3000 cm⁻¹ by irradiation with a sub-10-fs laser pulse. The spectral shaping of this laser pulse enabled us to selectively excite only the target vibrational frequency range (of the model compounds acetonitrile and benzene). Furthermore, the coherent molecular vibrational dynamics were compared between selective and nonselective excitation. The coherence of the molecular vibration persisted until 2-3 ps after photoexcitation, with the lifetime of this coherence being independent of whether the coherent molecular vibration was selective or nonselective excitation.