Ultrafast proton migration and Coulomb explosion of methyl chloride in intense laser fields

Abstract

We investigated the ultrafast proton migration and the Coulomb explosion (CE) dynamics of methyl chloride (CHCl) in intense femtosecond laser fields at the wavelengths of 800 nm (5.5 × 10 W/cm) and 400 nm (4 × 10 W/cm), respectively. Various fragment channels from molecular dication and trication were observed by coincidence momentum imaging through the measurement of their kinetic energy releases (KERs). The proton migration from different charged parent ions was analyzed from the obtained KER distributions. For the direct CE channel of CH + Cl and CH + Cl, the contribution of multiply excited electronic states and multicharged states is identified. In addition, the measurements of relative yields of the fragmentation channel at different laser wavelengths provide a selective control of proton migration for CHCl molecules in intense laser fields.

Molecular ionization of chloromethane in strong fields: nearest neighbor gateway to highly charged ions

“…We have varied this initial dissociation energy from 0.1 to 4 eV and determine it has little influence on the values of nm r C . This energy is also consistent with our measured CH 2 + fragment E of 3 eV and fragment energies measured by Ma et al [31].…”

“…We show the ion fragment energy is driven by Coulomb explosion and the internuclear separation at which ionization occurs during the dissociation of the molecule. At first multiple effects such as alignment [38], multiple fragmentation channels [31], wavepacket dynamics on multiple electronic states [39], rescattering [40], nonsequential double ionization [41], and other effects could seem to give a complex, if not uninterpretable spectra. Despite this, we show there is a clear and analytical predictability.…”

Controlling H3+ Formation From Ethane Using Shaped Ultrafast Laser Pulses

“…The intramolecular migration of hydrogen continues to be an active area of investigation in ultrafast science [1][2][3][4][5][6][7][8][9][10][11] with implications for topics ranging from combustion [12] to peptide dissociation [13] and characterizing conformational differences in molecules [14,15]. In some cases the migration of hydrogen leads to the formation of new molecular ions, such as H + 3 [5,[16][17][18][19][20][21], by processes such as H 2 roaming or double hydrogen migration [18,19,22,23].…”

Hydrogen migration in Coulomb explosion of cyclohexane to C2H4+ and C4H8+: Theoretical and experimental studies

“…The hydrogen migration process within a molecule in intense laser field has been an attractive research both theoretically and experimentally during the last several years . When irradiated with intense femtosecond laser pulses, neutral hydrocarbon molecules can experience dissociative ionization (DI) and Coulomb explosion (CE) processes in most cases, and intramolecular hydrogen migration processes are frequently observed among these two dynamical processes and are identified prior to skeletal bond breaking processes .…”

“…Later, using the similar method, they studied a series of molecules, such as 1, 3‐butadiene and allene, and the dissociation processes with hydrogen migration processes were still observed to result from CE of dications . Recently, Ding and coworkers studied eight CE channels originating from methyl chloride, and four hydrogen migration channels were identified from CE of molecular dication and trication through the measured kinetic energy releases (KER) distributions …”