Characterization of polycyclic aromatic compounds on surfaces using ion-beam-induced desorption and multiphoton resonance ionization

Fluid Flow and Effusive Desorption: Dominant Mechanisms of Energy Dissipation after Energetic Cluster Bombardment of Molecular Solids

“…29,36-38 Thickness was monitored using a quartz crystal microbalance (TM-400, Maxtek, Inc.) and verified with an atomic force microscope (Nanopics 2100, TLA Tencor Inc.) to be 400 nm with a surface roughness of 2 nm RMS. A Nd:YAG-pumped dye laser (Lambda-Physik ScanMate Pro) producing 280 nm 36 of light with 6 ns pulses and focused into a ribbon shape with peak power densities of 2×10 5 W/cm 2 was employed to intersect and photoionize the sputtered neutral flux. The kinetic energy and polar angle distributions were measured by recording the mass-selected signal amplitude for b[a]p as a function of position on the detector and time delay between the C 60 impact and photoionization event.…”

Isomeric identification and quantification of polycyclic aromatic hydrocarbons in environmental samples by liquid chromatography tandem mass spectrometry using a high pressure quadrupole collision cell

“…Isomeric identification is possible mainly by matching the retention times of unknowns with those of available standards. There have been many attempts to differentiate amongst isomers on the basis of their fragmentation patterns using electron ionization (EI), 4 multiphoton resonance ionization (MPRI), 15 chemical ionization (CI) 16 and tandem mass spectrometry (MS/ MS). 17,18,19 Because of the unusual structural stability of PAHs, a substantial amount of internal energy is required to cause extensive fragmentation.…”

An experimental and theoretical view of energetic C60 cluster bombardment onto molecular solids

“…A 200-ns pulse of ${\mathrm{C}}_{60}^{+}$ ions was used to bombard at normal incidence the b[a]p film. A Nd: YAG-pumped dye laser (Lambda-Physik ScanMate Pro) producing 280 nm [14] of light with 6-ns pulses and focused into a ribbon was used to photoionize the sputtered neutral species. An EARN distribution is measured by recording the mass-selected signal amplitude for b[a]p as a function of position on the detector and time delay between the firing of the C 60 ion source and the laser pulse.…”

“…[13] Two, the photoionization cross section is large enough to achieve the necessary sensitivity, and the rigidity of the molecule lessens the probability of photodissociation. [13][14][15][16] Three, the size of the molecule is the largest to be investigated experimentally concerning the mechanism of molecular emission.…”