VIBRATIONAL LADDER CLIMBING IN NO BY ULTRASHORT INFRARED-LASER PULSES

The anharmonic vibrational ladder of nitric oxide (NO) is climbed by i rradiating the molecule with femtosecond infrared (IR) pulses. The fre e-electron laser FELIX is tuned to lambda = 5.3 mu m with a bandwidth of Delta lambda = 0.3 mu m, corresponding to a pulse duration of 150 f emtoseconds. Transfer to the excited states of NO is monitored by 1+1 REMPI. Population is found up to upsilon '' = 5, the highest level wit hin reach of the IR bandwidth. The average transfer per step of the la dder is found to be 17%. (C) 1997 Elsevier Science B.V.