Fourier analysis of the nuclear flux density in diatomic molecules: A complementary tool to map potential-energy curves and to characterize vibrational wave functions
Pérez-Torres, Jhon F. – 2015
Pump-probe spectroscopy has allowed the construction of the nuclear probability density ρ(R,t) as a function of the internuclear bond distance (R) and the time (t) in diatomic molecules and consequent deduction of the nuclear flux density j(R,t). Thus, the two observables [ρ(R,t),j(R,t)] comprise a very detailed description of the nuclear motion in ultrafast molecular dynamics. Here a Fourier analysis of j(R,t) is proposed and compared with the already existing Fourier analysis of ρ(R,t). It is shown that the two power spectra ∣∣˜ρ(R,ω;T)|2 and ∣∣˜j(R,ω;T)|2 provide the same information in the frequency domain ω, but entirely different information in the spatial domain (i.e., along the R coordinate).