Dissociation of acetaldehyde in intense laser field: Coulomb explosion or field-assisted dissociation? Available to Purchase

Dissociation of acetaldehyde in moderate strong laser field of $1013–1014 W/cm2$ was investigated. Singly charged parent ion $CH3CHO+$ and fragmental ions $CH3+,$ $CHO+,$ $C2H4+,$ $O+,$ $CH2CHO+,$ and $H+$ were produced by 800 nm laser of 100 fs pulse duration and recorded by time-of-flight mass spectrometer. The $CH3+$ fragment further dissociated to $CH2+,$ $CH+,$ and $C+$ ions at higher intensity. Ab initio calculated results show that the singly-, doubly-, and triply charged parent ions are stable. So, the dissociation mechanism was not due to Coulomb explosion of multicharged ion. A field-assisted dissociation (FAD) theory, which assumes that only one bond undergoes dissociation while the rest of the molecular geometry stays unchanged, was employed to treat the dissociation dynamics. Accordingly, the dressed potential energy surfaces of the ground state for the parent and the fragment ions were calculated. Corresponding quasiclassical trajectory calculations show that the bond ruptures take place in the order of C–C, C–O, and C–H, agreeing with the observation. The observed angular dependence and charge distribution of the product ions can also be interpreted by the FAD theory.