OBSERVATION OF FRACTIONAL REVIVALS OF A MOLECULAR WAVE-PACKET

The study and control of molecular dynamics through the use of femtose cond laser techniques require an understanding of various orders of mo lecular wave-packet phenomena such as revivals. We present the observa tion of fractional revivals in a vibrational wave packet: the B state of the Br-2 molecule. Fractional revivals occur in anharmonic systems at characteristic times in the nonclassical regime when, due to dephas ing between vibrational eigenstates, the wave packet partially localiz es into sub-wave-packets. Half and quarter revivals were clearly obser ved, as well as indications of one-sixth revivals.