We present detailed quantum mechanical analysis of the complex resonan
ces observed in molecular predissociation. The complex features in the
photodissociation spectrum of Cs2 are reproduced well by the close-co
upling calculation including three channels. A very narrow resonance w
ith a linewidth of approximately 2 x 10(-7) cm-1 is predicted. It is s
hown that q reversal can occur in predissociation with only two channe
ls involved.