Laser-induced uitrafast vibrational wave packet dynamics in the NaK A~1#SIGMA#~+ state

摘要

We study the real-time vibrational dynamics of extremely cold NaK molecules excited to the electronic A~1 #SIGMA#~+ state isotope-selectively by means of time-resolved three photon ionization.For the isotopes ~23Na~39k and ~23Na~41K vibrational periods of T_A~(23,39) approx = 441 fs and T_A(23,41) approx =446 fs are determined.A detailed Fourier analysis proofs a weak perturbation of the wave packet caused by spin-orbit coupling of A and b~3 II~+ states.Pronounced fractional revivals of the fundamental oscillation are formed at T_frev~1,2(23,39) approx = 75 ps and T_frev~1,2(23,41) approx = 68 ps.The revival time allows a sensitive excitation energy E of the excited coupled system A~1#SIGMA#~+ - b~3 II.Spectrograms of the real-time data nicely reveal a strong fractional revival at T_frev~1,4=1/2T_frev~1,2.Further fractional revivals of weaker intensity at T_frev~1,6(23,39) approx approx 25 ps and T_frev~1,3(23,39) approx approx 50 ps occur for the lighter isotope.