Coincidence detection of dissociative fragments from CH3Cl

Abstract

In this letter, we describe the results of the detection, in coincidence, of CHn+ and Cl+ ions which result from the dissociation of CH3Cl after bombardment by 1 MeV He+ projectiles. The results confirm the existence of four dissociation channels, each with a kinetic energy release 0f 6.6 eV. The results suggest the channels could be due to a process in which 0, 1, 2,, or 3 hydrogens are dissociated from the methyl chloride and the remaining CH+n and Cl+ dissociate by a breaking of the carbon–chlorine bond. (AIP)

Formation of H3+ through Chloromethane Dication Fragmentation

“…However, the CH 3 Cl 2+ internal energy that one may measure should not correspond to the theoretical energy difference between the barrier height of the CH 3 Cl 2+ (X 3 A 2 ) PES and its asymptote (of ∼9 eV), but to the energy difference between the X 3 A 2 /1 1 A 1 crossing and the lowest dissociation limit (i.e., H 3 + (X 1 A 1 ) + CCl + (X 1 Σ + )), which is ∼5.2 eV (Figure ). This value agrees with the KER measured by Monce et al , (∼4.6 eV). The KER measured by Ruhl et al of 3.4 ± 1 eV is distinctly lower than the present theoretical and previous experimental determinations.…”

“…Laboratory experiments showed that single or multiple ionizations of CH 3 Cl produce H + , Cl + , CCl + , HCl + , CH 2 Cl + , CH 2 + , CH 3 + , and H 3 + ions and the corresponding neutral species. − Here, we will focus on the H 3 + formation from CH 3 Cl 2+ because of the crucial importance of this ion in astrophysics by planetary and atmospheric chemistry. Our results show that the CH 3 Cl 2+ → H 3 + + CCl + reaction can be an efficient pathway for the formation of H 3 + in astrophysical media and in the upper atmosphere.…”

Strong-field ionization of CH3Cl: proton migration and association

“…In addition, methyl chloride has been found in a stable form in the interstellar medium. 23 The fragmentation of CH 3 Cl has been studied extensively using ion bombardment, 24,25 synchrotron radiation, [26][27][28][29] and femtosecond lasers. [30][31][32] H n + (n = 1-3) and HCl + formation during the photodissociation of CH 3 Cl has been of interest for many years.…”

Dynamic Effects on the Ionization-Induced Reactions of Methyl Halides: Quantum Mechanical and Molecular Dynamics Studies

“…The ionization-induced fragmentation of methyl halides is of great interest, because the methyl chloride is present in the stratosphere and interstellar medium and contributes to ozone depletion in the stratosphere. For this reason, numerous experimental and theoretical studies have been intensively conducted, with particular emphasis on the two important processes: (i) ionization − and (ii) subsequent fragmentation reaction, ,,− which together constitute the ionization-induced fragmentation reaction. Many experiments have shown that the doubly ionized methyl chloride yields not only H + and H 2 + but also H 3 + as well as other substances such as HCl + and Cl + .…”