High-resolution infrared spectra of HCF3 in the ν6 (500 cm-1) and 2ν6 (1000cm-1) regions:: rovibrational analysis and accurate determination of the ground state constants C0 and D0K

The high-resolution infrared spectrum of HCF3 was studied in the v(6) fundamental (near 500 cm(-1)) and in the 2v(6) overtones (near 1000cm(-1)) regions. The present study reports on the analysis of the hot bands in the v(6) region, as well as the first observation and assignment of the 2v(6)(-/+2) perpendicular band. Using v(6), 2v(+/-2)-v(6)(+/-1) and 2v(6)(-/+2) experimental wavenumbers, accurate coefficients C-0 and D-K(0) of the K-dependent ground-state energy terms were obtained, using the so-called "loop method." Ground-state energy differences Delta(K,J) = E-0(K,J) - E-0(K - 3,J) were obtained for K = 3-30. A least-squares fit of 81 such differences gave the following results (in cm(-1)): C-0 = 0.1892550(15); D-K(0) = 2.779(26) x 10(-7). (C) 2003 Elsevier Science (USA). All rights reserved.