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oai:docta.ucm.es:20.500.14352/1314072026-02-04T00:48:19Zcom_20.500.14352_14col_20.500.14352_15

00925njm 22002777a 4500 dc Bañares Morcillo, Luis author Marggi Poullaín, Sonia author Recio Ibáñez, Pedro author Cachón, Javier author Zanchet, Alexandre author 2023-08-09 The photodissociation dynamics leading to the C–N bond cleavage in methylamine (CH3NH2) are investigated upon photoexcitation in the blue edge of the first absorption A-band, in the 198–204 nm range. Velocity map images of the generated methyl (CH3) fragment detected in specific vibrational modes, i.e., ν = 0, ν1 = 1, and ν2 = 1, through resonance enhanced multiphoton ionization, are presented along with the corresponding translational energy distributions and the angular analysis. The experimental results are complemented by high-level ab initio calculations of potential energy curves as a function of the C–N bond distance. While a similar single Boltzmann-type contribution is observed in all the translational energy distributions measured, the speed-dependent anisotropy parameter obtained through the angular analysis reveals the presence of two different mechanisms. Prompt dissociation through the conical intersection between the A1A' first excited state and the ground state located in the exit channel is, indeed, revealed as a minor channel. In contrast, slow dissociation on the ground state, presumably from frustrated N–H bond cleavage trajectories, constitutes the major reaction pathway leading to the methyl formation. Javier Cachón, Pedro Recio, Alexandre Zanchet, Sonia Marggi Poullain, Luis Bañares; Photodissociation dynamics of methylamine in the blue edge of the A-band. II. The NH2 + CH3 channel. J. Chem. Phys. 14 August 2023; 159 (6): 064302. https://doi.org/10.1063/5.0159855 0021-9606 1089-7690 10.1063/5.0159855 https://hdl.handle.net/20.500.14352/131407 https://doi.org/10.1063/5.0159855 https://pubs.aip.org/aip/jcp/article/159/6/064302/2906247 Photodissociation dynamics of methylamine in the blue edge of the <i>A</i>-band. II. The NH2 + CH3 channel