Efficient ejection of H3+ from hydrocarbon molecules induced by ultrashort intense laser fields

Abstract

The ejection processes of hydrogen molecular ion H(3)(+) from 12 kinds of hydrocarbon molecular species, methanol, ethanol, 1-propanol, 2-propanol, acetone, acetaldehyde, methane, ethane, ethylene, allene, 1,3-butadiene, and cyclohexane, induced by intense laser fields (approximately 10(14) W/cm(2)) have been investigated by time-of-flight mass spectroscopy. The observation of the H(3)(+) production with the kinetic energy range of 3.5-5.0 eV from doubly ionized ethylene, allene, 1,3-butadiene, and cyclohexane, which have no methyl groups, showed the existence of the ultrafast hydrogen migration processes that enables three hydrogen atoms to come together to form H(3)(+) within a hydrocarbon molecule.

Coherent vibrations in methanol cation probed by periodic H3+ ejection after double ionization

“…From the number of events at Δt~500 fs in the high E kin region above 3.5 eV, the relative yields of the pathways (1), (2), (3), and (4) in our measurements are derived to be 1:1:0.07:3.6, respectively, showing that the three body explosion pathway (4) has the largest ion yield and the pathway (3) is a minor pathway.…”

“…For example, H 3 + formed through a bimolecular reaction, H 2 + +H 2 →H 3 + +H, can protonate a neutral molecule X by a subsequent bimolecular collision, H 3 + +X→HX + +H 2 , which may lead to further subsequent interstellar chemical reactions. It has also been shown that H 3 + can be emitted from hydrocarbon molecular dication prepared by electron impact ionization 2 , by extreme ultraviolet photoionization 3 , and by irradiation of intense femtosecond laser pulses [4][5][6] . The formation of H 3 + from allene [7][8][9] and the formation of HD 2 + from CD 3 OH 10 showed that migration of hydrogen atoms can proceed in the formation of H 3 + .…”

Subfemtosecond steering of hydrocarbon deprotonation through superposition of vibrational modes

“…PES for ground and excited states of the neutral, cation and dication states of acetylene were calculated on the CASSCF [10,10], [9,10] and [8,10] level of theory, respectively, using the program package MOL-PRO 35 with the 6-311þþG** basis set as well as the dipole moments and transition dipole moments. Two-dimensional PES were calculated along the symmetric and anti-symmetric stretching coordinate with a step size of 0.05 a.u..…”

“…Breaking of the hydrogen bonds is one of the most important dynamic reactions in the chemistry related to biology, combustion and catalysis, motivating considerable efforts to monitor and ultimately control the process. It has been studied in great detail, where efficient strong-field-induced proton ejection was reported [7][8][9][10][11][12][13][14] . Dynamic charge localization 11 and concerted fragmentation 12 scenarios were suggested to explain the origin of the high kinetic energies of the ejected protons.…”

Hydrogen scrambling in H3+generation from ethane induced by ultrashort intense laser fields

“…When hydrocarbon molecules are exposed to an intense laser field, a variety of dynamical processes originating from ultrafast motion of hydrogen atoms proceed such as ultrafast hydrogen migration and ejection of H 3 + , as has been shown in our recent studies on methanol [1], ethane [2][3][4], and other hydrocarbon molecules [2]. In the present study, in order to clarify how hydrogen atoms and/or protons migrate within an ethane molecule and to what extent the hydrogen atoms and protons exchange their positions among each other, we measured coincidence momentum imaging maps of fragment ions produced from ethane exposed to an intense laser field.…”