Photodissociation of vibrationally excited SH and SD radicals at 288 and 291 nm: The S(D-1(2)) channel

摘要

Ultraviolet photodissociation of SH (X (2)Pi, upsilon(')=2-7) and SD (X (2)Pi, upsilon(')=3-7) has been studied at 288 and 291 nm, using the velocity map imaging technique to probe the angular and speed distributions of the S(D-1(2)) products. Photodissociation cross sections for the A (2)Sigma(+)<- X (2)Pi(upsilon(')) and (2)Delta <- X (2)Pi(upsilon(')) transitions have been obtained by ab initio calculations at the CASSCF-MRSDCI/aug-cc-pV5Z level of theory. Both the experimental and theoretical results show that SH/SD photodissociation from X (2)Pi (upsilon(')<= 7) proceeds via the repulsive wall of the A (2)Sigma(+) state. The angular distributions of S(D-1(2)) indicate that the dissociation approaches the sudden recoil limit of the A (2)Sigma(+) state, yielding strongly polarized fragments. The S(D-1(2)) atoms are predominantly produced with total electronic angular momentum perpendicular to the recoil axis. (c) 2007 American Institute of Physics.