The Infrared Diode Laser Spectroscopy of the ν2+ ν5− ν2Hot Band of Acetylene

✍ Scribed by Svatopluk Civiš; Zdeněk Zelinger; Keiichi Tanaka

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 173 KB
• Volume: 187
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1997.7471

✦ Synopsis

The infrared diode laser spectrum of the n 2 / n 5 0 n 2 hot band of acetylene has been observed within the discharge plasma of acetylene diluted in He. The concentration of acetylene in the n 2 state was modulated by applying a few kHz of ac current, and the spectrum of the hot band was recorded selectively by the discharge modulation technique. In total, 46 P, R, and Q-branch lines have been assigned to the n 2 / n 5 0 n 2 hot band and molecular constants including the band origin 727.59318(27) cm 01 were derived. The lifetime of acetylene in the n 2 state was measured to be about 1 ms, proving that the n 2 state is metastable. The collisional relaxation rate constant of acetylene in the n 2 state by helium was measured to be k Å 8.01 { 0.19 1 10 014 cm 3 molec 01 s 01 .