Enhanced Raman spectrum of pyrazine with the aid of resonant electron dynamics in a nearby cluster

Considerable enhancement of the electric dipole excitation in a pyrazine molecule is computationally demonstrated even under the nonresonant condition with the aid of resonant electron dynamics in a nearby linear Na4 cluster. A real-time and real-space electron dynamics simulation based on time-dependent density functional theory illustrates the details of the enhanced electric dipole excitation through analysis of the time-dependent dipole moment induced in the pyrazine molecule. Specific vibrational normal modes in the molecular plane of pyrazine are found to effectively couple with the photoinduced electronic oscillation of Na4.