Time of Flight Measurement of N2 and N2(+) Lifetimes.
Technical rept. May-Oct 68,
STANFORD RESEARCH INST MENLO PARK CA
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The principal aim of this short research effort was to test a new method of exciting neutral molecules in selected states and measuring their lifetimes. Measurements were carried out on the B triplet Pi g state of nitrogen, which decays with emission of the nitrogen first positive bands. A neutral beam of excited neutral nitrogen molecules was produced from a beam of nitrogen molecular ions by near-resonant charge transfer in alkali vapor, and lifetimes were measured by observing the spatial decay along the beam path of radiation from the fast moving molecules. Lifetimes obtained from the first positive bands agree with and confirm results that Jeunehomme obtained via pulsed excitation of a static gas. In a second experiment, lifetimes of the three vibrational levels of the A doublet Pi u state of the singly ionized nitrogen molecule excited in the ion source were obtained from the spatial decay of the Meinel bands. These are believed to be the first unambiguous lifetime measurements for the A state. The technique has important advantages over conventional methods for determining lifetimes in cases where cascading, diffusion, or collisional quenching can interfere with measurements in static gases. Author
- Atomic and Molecular Physics and Spectroscopy