Multiple coherent states semiclassical representation for first principles molecular dynamics and dipole absorption spectra calculations of lateral interactions for CO on Cu(100)

Lateral interactions between carbon monoxide molecules adsorbed on Cu(100) surfaces and CO2 power spectrum are investigated via semiclassical initial value representation (SCIVR) molecular dynamics. An analytical potential is extended to include long range dipole interactions between coadsorbed molecules. Then, the dipole absorption spectra for several coadsorbed molecules are calculated using the multiple coherent states approximation of the time-averaging representation of the SCIVR propagator. Results show strong resonances between coadsorbed molecules as observed by past experiments. Resonances turn into dephasing when isotope substitutions are performed. On Figure the absorption spectrum of CO atoms adsorbed in a realistic 0.5 monolayer fashion is reported without dipole coupling on, dipole coupled isotopic mixitures on and the resonant layer, i.e. without isotope substititions. Instead, the CO2 spectrum is calculated on-the-fly and the strong anharmonic Fermi resonances are faithfully reproduced.