Journal of Chemical Physics, Vol.100, No.8, 5656-5665, 1994
Guided-Ion Beam Measurements of N++h2O Charge-Transfer and Chemical-Reaction Channels
Guided-ion beam measurements of N+ +H2O charge-transfer and chemically reactive channels are presented for collision energies ranging from 0.1 eV to 20 eV c.m. The charge-transfer reaction is not as efficient as expected considering the favorable Franck-Condon overlap at resonance. The analysis of product-ion time-of-flight spectra demonstrates that energy transfer is efficient in orbiting collisions at all investigated collision energies. At low collision energies, formation of NO+, and HNO+ and/or NOH+, is observed. The chemically reactive channels exhibit a near 1/E(T) dependence at low collision energies. Above 0.5 eV, the HNO+/NOH+ cross section drops abruptly below the instrumental sensitivity. The NO+ cross section exhibits a minimum at 1.2 eV, followed by an increase in cross section with energy reaching a maximum of 4 X 10(-16) CM2 at 7 eV before decreasing again. The decline at higher energies is partly attributed to a dissociative loss of the product ions. O+ formation is observed at and above the thermodynamic threshold associated with the O+ + N + 2H asymptotic limit.
Keywords:ORBITAL ANGULAR-MOMENTUM;SUPRATHERMAL ENERGIES;TRIATOMIC-MOLECULES;CROSS-SECTION;COLLISIONS;N+;SPECTROSCOPY;IONIZATION;DYNAMICS;STATES