title: Imaging the pair-correlated HNCO photodissociation: the NH(a1Δ) + CO(X1Σ+) channel.
abstract: The NH(a(1)Δ) + CO(X(1)Σ(+)) product channel for the photodissociation of HNCO at 201 nm was investigated using the sliced velocity map ion imaging technique with the detection of NH(a(1)Δ) products via (2 + 1) resonance enhanced multiphoton ionization (REMPI). Images were measured for the NH(a(1)Δ) rotational states in the ground and vibrational excited states (v = 0 and 1). Correlation between the NH(a(1)Δ) and CO rovibrational state distributions were determined from these images. Experimental results show that the vibrational distribution of the CO fragment in the NH(a(1)Δ) + CO(X(1)Σ(+)) channel peaks at v = 1. The negative anisotropy parameter measured for the NH(a(1)Δ) (v = 0 and 1|j) products indicates a direct dissociation process for the N-C bond cleavage in the S1 state. A bimodal CO rotational distribution was observed, suggesting that HNCO dissociates in the S1 state in two distinctive pathways.
authors.affiliation: Department of Chemical Physics, University of Science and Technology of China , Hefei 230026, China.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Zhang
authors.forename: Zhichao
authors.initials: Z
authors.lastname: Chen
authors.forename: Cunshun
authors.initials: C
authors.lastname: Huang
authors.forename: Yang
authors.initials: Y
authors.lastname: Chen
authors.forename: Dongxu
authors.initials: D
authors.lastname: Dai
authors.forename: David H
authors.initials: DH
authors.lastname: Parker
authors.forename: Xueming
authors.initials: X
authors.lastname: Yang
mesh_terms: D002248:Carbon Monoxide / Q000737:chemistry*; D003485:Cyanates / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D055668:Photochemical Processes
chemical_list: D003485:Cyanates; D002248:Carbon Monoxide; D006859:Hydrogen; D009584:Nitrogen; C005057:isocyanic acid