Dissociative ionization of CH2Br2 in 800 and 400 nm femtosecond laser fields

Dissociative Ionization of Molecular CF2Br2 under 800 and 400 nm Intense Femtosecond Laser Fields

The interaction between the CF2Br2 molecule and 800/400 nm intense femtosecond laser fields is investigated by direct current (dc) sliced velocity mapping imaging implementation. By analyzing the kinetic energy release distribution and angular distribution of fragment ions, the dissociation channels along C-Br bond cleavage have been determined. The isotropic structure of the angular distribution for CF2Br+ ions is attributed to the coupling between the excited states. Additionally, a unique elimination channel of CF2Br2+ → CF2 + Br2+ has been observed and identified in the case of 400 nm laser field, in which the two C-Br bonds break asynchronously.

Dissociative Ionization and Coulomb Explosion of Molecular Bromocyclopropane in an Intense Femtosecond Laser Field

The dissociative ionization and Coulomb explosion of molecular bromocyclopropane (BCP) has been experimentally investigated by time-of-flight mass spectrum and dc-slice imaging technology. The sliced 2D images, kinetic energy releases and angular distributions of the fragment ions are obtained under the intense femtosecond laser fields (8.0 × 1013⁻2.0 × 1014 W/cm²). The results indicated that the low kinetic energy release (KER) components come from dissociative ionization of BCP⁺, while the high KER components come from Coulomb explosion of BCP2+. The chemical reaction path of BCP⁺ has been calculated by ab initio calculation, furthermore, the C-Br bond cleavage involved Coulomb explosion channels have been revealed, and the corresponding dehydrogenation mechanism has been confirmed.