Vibrational ladder climbing in NO by (sub)picosecond frequency-chirped infrared laser pulses

The anharmonic vibrational ladder of nitric oxide (NO) is climbed by irradiating the molecule with chirped intense (sub)picosecond infrared (IR) pulses (Imax=1.0×1010 W/cm2). The chirp of the broadband IR (hν=1850 cm−1, Δhν=50 cm−1) pulse from a free-electron laser is controlled by a pulse shaper. Transfer up to the excited vibrational state X 2Π1/2(v=3) of NO shows a strong enhancement when the frequency chirp of the IR pulses follows the consecutive anharmonic vibrational transitions.