Weak Combination Bands in the 3-μm Region of Ethane

✍ Scribed by M. Hepp; M. Herman

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 177 KB
• Volume: 197
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1999.7893

✦ Synopsis

The infrared spectrum of ethane in the region of the CH-stretching fundamental vibrations, between 2600 and 3300 cm Ϫ1 , was recorded with a Bruker IFS120HR Fourier transform spectrometer. Jet-cooled and room-temperature conditions were used at 0.01 and 0.005 cm Ϫ1 instrumental resolution, respectively. Ten weak combination bands were observed and vibrationally assigned, in addition to the three principal bands in the region ( 5 , 7 , and 8 ϩ 11 ( component)). A stack-by-stack analysis was performed for five of the combination bands. Their origins were determined as follows: 8 ϩ 12 ( component) at 2665.1512(30) cm Ϫ1 , 2 ϩ 6 at 2753.326(32) cm Ϫ1 , 6 ϩ 11 at 2844.13069(75) cm Ϫ1 , 8 ϩ 11 (Ќ component) at 2930.705(90) cm Ϫ1 , and 4 ϩ 10 at 3255.568(50) cm Ϫ1 . Effective rovibrational parameters were obtained for the corresponding upper states. New information was also obtained on the five remaining combination bands. Their approximate origins are: 8 ϩ 12 (Ќ component) at 2660 cm Ϫ1 , 2 ϩ 4 ϩ 12 at 2860 cm Ϫ1 , 4 ϩ 2 9 ϩ 12 at 3090 cm Ϫ1 , 3 4 ϩ 8 ϩ 9 at 3157 cm Ϫ1 , and 4 ϩ 2 8 at 3225 cm Ϫ1 .