Vibrational amplitude profile of molecular vibrational modes for vibrational mode assignment

Ultrashort pulse lasers with 6- and 20-fs durations were utilized for phthalocyanine thin film sample to induce several vibrational modes and vibration amplitude spectra were determined by multi-wavelength measurement technique. From the spectra we could identify the electronic states, which couple to two vibrational modes with frequencies of 670 and 750 cm−1. It was shown that the vibrational amplitude profile obtained by the method can be used for providing information for the assignment of the vibrational mode.