title: Photodissociation of ClN(3) at 157 nm: Theory suggests a pathway leading to cyclic N(3).
abstract: The photodissociation dynamics of chlorine azide (ClN(3)) at the 157 nm region was studied theoretically using the multireference configuration interaction method and the complete active space self-consistent field direct dynamics method. The excitation at the 157 nm region was assigned to the 4 (1)A(')(S(7))<--X (1)A(')(S(0)) transition. A likely pathway for the formation of cyclic N(3) after this transition was identified by direct dynamics as follows: ClN(3) excited to 4 (1)A(')(S(7)) dissociates after about 40 fs to excited N(3)(2 (2)A('), with about 44 kcal/mol internal energy) +Cl((2)P). This vibrationally hot N(3)(2 (2)A(')) goes diabatically through a conical intersection with N(3)(1 (2)A(')) at 44 fs onto 1 (2)A('). At 19 fs later and repeatedly after every 55 fs, N(3)(1 (2)A(')) crosses and trickles down via Coriolis coupling to N(3)(2 (2)A(")/ (2)B(1)) state, which has a potential minimum at the cyclic-N(3) structure. Some fraction of N(3)(2 (2)A(")/ (2)B(1)) produced will survive dissociation and will be found as the cyclic N(3), and some other fraction will eventually dissociate to N((2)D)+N(2) over a high barrier found previously.
authors.affiliation: Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA.
authors.forename: Ioannis S K
authors.initials: IS
authors.lastname: Kerkines
authors.forename: Zhi
authors.initials: Z
authors.lastname: Wang
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Keiji
authors.initials: K
authors.lastname: Morokuma