H3Si37Cl Revisited with High Resolution: The Ground State and the v2 = 1; v3 = 1, 2, and 3; v5 = 1; v6 = 1 and 2; and v3 = v6 = 1 States

✍ Scribed by H. Bürger; S. Bailleux; G. Graner; S. Bosc; Y. Hennequin

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 447 KB
• Volume: 196
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1999.7867

✦ Synopsis

The infrared spectrum in the range 400 -1600 cm Ϫ1 of isotopically pure H 3 Si 37 Cl has been recorded at high resolution (2.4 -6.6 ϫ 10 Ϫ3 cm Ϫ1 ) and analyzed. Fifteen bands have been studied, namely the four fundamentals 3 (543.968 cm Ϫ1 ), 6 (663.738 cm Ϫ1 ), 2 (947.982 cm Ϫ1 ), and 5 (950.657 cm Ϫ1 ), the overtone bands 2 3 , 2 6 0 , and 2 6 ϯ2 , the combination band 3 ϩ 6 , and seven hot bands. Improved ground state constant parameters have been obtained, including all four sextic distortion constants. As for the J-independent parameters A 0 , D K 0 , and H K 0 , they were determined mainly through the "loop method" involving 6 , 2 6 ϯ2 , and 2 6 ϯ2 -6 Ϯ1 and checked through the strong interactions between 2 and 5 , producing some "forbidden lines." The 2 / 5 dyad was fitted with success using two different reduced Hamiltonians. Concerning 3 and 6 , in spite of their relatively large separation, a Coriolis interaction could be evidenced. In both 2 / 5 and 3 / 6 interacting systems the sign of the interaction was found positive. As for the overtones, 2 3 was treated as isolated and 2 6 0 and 2 6 ϯ2 as linked together by an l(2, 2) interaction. The data on the v 3 ϭ v 6 ϭ 1 levels were obtained mainly from the two hot bands 3 ϩ 6 -3 and 3 ϩ 6 Ϫ 6 , and marginally from the weak band 3 ϩ 6 , and also fitted as for an isolated level. A weak x,y-Coriolis interaction with level crossing between K/(kl Ϫ 1) ϭ 21 and 22, and a local l(1, Ϫ2) resonance at K ϭ 13/kl ϭ Ϫ15 between 2 3 and 5 were furthermore detected.