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Updated: Jun 24, 2026

Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies
Published on: December 18, 2015
The C7 cluster: structure and infrared frequencies
J R Heath1, R A Sheeks, A L Cooksy
1Department of Chemistry, University of California, Berkeley 94720, USA.
Abstract:
Observation and characterization of the C7 cluster are reported. Carbon clusters are produced by laser vaporization of a graphite target followed by supersonic expansion of the vaporized material within a gas dynamically focused argon jet. Thirty-six sequential rovibrational lines of the nu 4 antisymmetric stretch fundamental of C7 are probed by gated detection of diode laser absorption. The observed spectrum is characteristic of a symmetrical linear molecule. Analysis of the spectrum indicates an effective average bond length of 1.2736(4) angstroms and a vibrational frequency of 2138.1951(10) reciprocal centimeters, in excellent agreement with ab initio calculations. This work will facilitate the astrophysical detection of this cluster.
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