The ν1+ν3 and the ν1+ν2+ν41+ν5−1 Combination Bands of 13C2H2. Linestrengths, Broadening Parameters, and Pressure Shifts

✍ Scribed by Mitsuhiro Kusaba; Jes Henningsen

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 259 KB
• Volume: 209
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.2001.8426

✦ Synopsis

The ν 1 + ν 3 and the ν 1 + ν 2 + ν 1 4 + ν -1 5 combination bands of 13 C 2 H 2 at 6521.9 and 6535.1 cm -1 , respectively, are studied with diode laser spectroscopy. Line center wavelengths have been determined with 0.00012-nm standard uncertainty up to J = 40 for ν 1 + ν 3 and up to J = 25 for ν 1 + ν 2 + ν 1 4 + ν -1 5 . Linestrengths are modeled with a Herman-Wallis expansion

Collision broadening parameters are extracted from Voigt fits to the line profiles and can be modeled for both bands by the analytical expression γ = 5.221 -0.0839 |m| + 1.46 exp(-0.45 |m|) MHz/mbar, indicating independence of vibrational state. Collisional narrowing is studied on selected lines and the model dependence of linestrengths and broadening parameters is determined. Pressure shifts are studied in ν 1 + ν 3 , and a characteristic difference in the shifts for the P-branch and the R-branch is explained in terms of a simple ad hoc assumption about the level shifts. These bands have a potential for providing wavelength standards for optical fiber communication.