Photodissociation of ICN at 266 nm and BrCN at 230 nm using brute force orientation

This Letter presents measurements of the CN fragment from photolysis of BrC N at 230 nm and ICN at 266 nm. Supersonically cooled samples were spatially oriented using a strong uniform electric field. An enhanced signal from th e CN fragment of ICN was seen when the dissociation laser was polarized par allel to the orientation field, and the degree of enhancement agreed with c alculation of a pure parallel transition. Dissociation of BrCN displayed an enhancement which fell below the upper limit assuming a pure parallel tran sition at a rotational temperature of 1.5 K, implying contributions from a perpendicular transition. (C) 1999 Elsevier Science B.V. All rights reserve d.