Collision, ion/neutral

The gas pressure in the first hexapole section is influenced by gas leaking in from the inlet system and, at about 10" mbar, is higher than desirable if excessive ion/neutral collisions are to be prevented. Therefore, the first hexapole is separated from the second hexapole section by a small orifice, which allows ions to pass through. 

Role of Excited States In Ion-Neutral Collisions Table I. continued... 

A considerable array of instrumentation has been developed in the past 10-15 years for the study of ion-neutral collisions. Such instruments can be classified into several categories, with each type having features that make it suitable for investigating particular aspects of the ion-neutral interaction. The present discussion is limited to those experimental techniques that have been specifically applied for examining the role of excited states in these processes. 

Energy transfer occurring in nonreactive neutral-neutral collisions is a very active field of investigation.230 Important contributions to the understanding of collisional energy-transfer processes have also resulted from various studies of nonreactive ion-neutral collisions. The modes of energy transfer that have been investigated for the latter interactions include vibrational to relative translational (V-T), vibrational to vibrational (V-V), translational to vibrational (T-V), translational to rotational (T-R), vibrational to rotational (V-R), translational to electronic (T-E), and electronic to translational (E-T). 

In the preceding we have reviewed collisional deactivation of ions in thermal or low-translational-energy collisions. An interesting phenomenon, however, is the observation of E-T and V-T transfers in ion-neutral collisions at translational energies of several hundred electron volts. These transfers cause the so-called superelastic peaks observed in translational-energy measurements of the scattered ions. Electronic to translational energy transfer was observed in collisions of 3.5-keV N+ with rare-gas atoms and with 02.255 256... 

Role of Excited States in Ion-Neutral Collisions 2. Energy Exchange a. Electronic Excitation... 

IV. EXCITED PRODUCTS FROM ION-NEUTRAL COLLISIONS (ELECTRONIC, VIBRATIONAL AND ROTATIONAL EXCITATION)... 

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