Vibrationally-induced electronic population inversion with strong   femtosecond pulses
  We discover a new mechanism of electronic population inversion using strong femtosecond pulses, where the transfer is mediated by vibrational motion on a light-induced potential. The process can be achieved with a single pulse tuning its frequency to the red of the Franck-Condon window. We show the determinant role that the sign of the slope of the transition dipole moment can play on the dynamics, and extend the method to multiphoton processes with odd number of pulses. As an example, we show how the scheme can be applied to population inversion in Na2. 
Pablo Sampedro, Bo Y. Chang, Ignacio R. Sola
physics.atom-ph quant-ph