Selective vibrational excitations in the OX (X = F, Cl, Br, I) molecules

Using ab initio calculated potential energy and electric dipole moment functions for the X 2II states of OF, OCl, OBr and OI, two models have been tested to selectively populate their vibrational modes by ultrashort coherent light pulses. For a given form of the pulses either a perturbative approach using discrete vibrational eigenstates and electric dipole transition moment matrix elements or a wavepacket propagation technique were used. The optimisation of the pulse parameters and the mechanisms of the multiphoton processes are discussed. For the target level v = 10 populations of more than 60% have been achieved in all four molecules. For act it was possible to populate selectively all target levels between v = 2 and v = 15 using chirped pulses.