Detection of the Excited-State NH2 ((A)over-tilde (2)A(1)) in the Ultraviolet Photodissociation of Methylamine

作者：Onitsuka Yuuki; Yamasaki Katsuyoshi; Goto Hiroki; Kohguchi Hiroshi^*

来源：Journal of Physical Chemistry A, 2016, 120(43): 8584-8589.

DOI：10.1021/acs.jpca.6b08674

Ion-imaging and dispersed fluorescence spectroscopy are employed for the photodissociation dynamics study of methylamine in the photolysis wavelength range 205-213 nm. The methyl radical product is found to populate a wide range of ro-vibrational states, among which the CH3 fragment generated in the v = 0 state shows a bimodal kinetic energy distribution. The internal energy analysis of the NH2 counterproduct indicates that a lower kinetic energy component, which was observed only with the CH3(v=0) fragment, energetically matches the electronically excited (A) over tilde (2)A(1) state. The dispersed fluorescence spectrum, whose band structure is assigned to the (A) over tilde (2)A(1) -> (X) over tilde B-2(1) transition, provides evidence of the CH3(v=0) + NH2((A) over tilde (2)A(1)) pathway. The branching mechanism of the product pathway is discussed in terms of nuclear dynamics in the long-range region, where the conical intersection between the excited- and ground-state potential energy surfaces can play a significant role.

• 出版日期2016-11-3