Vibrational resonance energy transfer and dephasing in liquid nitrogen near its boiling point: Molecular computations

摘要

On the basis of current models of oscillatorndash;oscillator and oscillatorndash;anharmonicityndash;lattice coupling, the band broadening increments leading to the spontaneous width of the (nearhyphen;isotropic) Raman stretching fundamental of liquid nitrogen near its boiling point are predicted. Using known constants of the atomndash;atom Lennardhyphen;Jones potential and known dynamic autocorrelation times of the system, the observed spontaneous bandwidth of 0.067 cmminus;1and its Lorentzian band contour are satisfactorily reproduced (0.07 cmminus;1) by a vibrational dephasing mechanism if it is assumed that motional narrowing takes place through a modulation process decaying on the same fast time scale as that of the velocity correlation between two nitrogen molecules. On the other hand, resonance energy transfer contributes less than 1percnt; to the band broadening.