Selective photodissociation of O–H and O–D bonds from ground vibrational state of HOD using simple UV pulses

Selective cleaving of both O–H and O–D bonds in HOD is achieved using reasonably simple UV pulses to excite the HOD molecule in its ground vibrational state to the repulsive first excited $Ã(B11)$ surface. Detailed theoretical analysis of population transfer and flux in the$H+O–D∕H–O+D$ channels reveals an important preparatory role for the cross-talk between the participating levels and a possible role for the beat structure of the population transfer oscillations in facilitating selective dissociation. Excitation using a $50fs$ single color $67169cm−1$ laserpulse achieves a branching ratio $H+O–D∕H–O+D=5.64$ with 82% flux in the$H+O–D$ channel and 15% in the $H–O+D$ channel. A two color $50fs$ laser pulse with frequencies of 54 920 and $52303cm−1$ provides a branching ratio of $H–O+D∕H+O–D=2.83$ and 52% flux in the $H–O+D$ channel and 18% in the $H+O–D$ channel.