Dissociative ionization of acetonitrile in intense femtosecond laser fields

Boran Y., Kolomenskii A. A. , Sayrac M., KAYA N., Schuessler H. A. , Strohaber J.

JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, vol.50, no.13, 2017 (SCI-Expanded) identifier identifier


We investigate the formation of positively charged fragments of acetonitrile (CH3CN) in intense 800 nm, 50 fs pulses of radiation using a reflectron time-of-flight (TOF) ion mass spectrometer. Singly-charged ions of CHnCN+ (n = 0-3), HCN+, CN+, CH3+, CH2+, CH+, C+ and H+; and the multiply charged ions of C2+, C3+, CH22+, and CH23+ were observed in the mass spectra. Quantum chemical calculations with GAMESS (General Atomic and Molecular Electronic Structure System) of appearance energies for the parent molecule and daughter fragments have been carried out. Intensity dependent ion yields were measured for intensities between 4.4 x 10(13) W cm(-2) and 3.3 x 10(14) W cm(-2). Angular distributions of most fragment ions were found to peak when the laser radiation was polarized parallel to the TOF axis, while the carbon ions, C+ and C2+, were found to have maxima for both polarizations parallel and perpendicular to this axis. Kinetic energies of H+ fragments were experimentally measured and three different photo dissociation mechanisms were identified.