15min:

E. T. WHITE, J. TANG AND T. OKA, Department of Chemistry, The University of Chicago, Chicago, IL 60637.

Ab initio calculations predict that protonated methane, CH₅⁺, has three low energy structures that are practically equal in energy and that barriers separating their 120 equivalent minima are low. Thus CH₅⁺ provides a new prototype of spectroscopic specimen in which the five equivalent protons are attached to the central carbon atom. We have observed, using our difference frequency spectrometer and the velocity modulation technique, a weak but rich spectrum of a carbocation containing one carbon. We believe they are transitions of CH₅⁺ due to the formally forbidden CH stretch band based on their plasma chemical behavior and agreement with the conclusion of predissociation spectroscopy of CH₇⁺. A preliminary observational result will be reported.