Analysis of the High-Resolution Fourier Transform Infrared Spectra of the ν3and ν5Bands of Thionylimide (HNSO)

High-resolution FTIR spectroscopy of HNSO—Analysis of the highly perturbed ν4, ν6 and 2ν5 bands

“…A series of trial fits were therefore performed with the v 5 = 2 state and various resonance interaction terms explicitly included. An initial set of rotational constants and band origin for the v 5 = 2 state were calculated based on the known v 5 = 1 state values [21] and the ground state constants. The 2m 5 band centre, rotational constants and centrifugal distortion constants up to quartic level were all permitted to vary in the fit, whilst higher order centrifugal distortion constants were fixed to the ground state values.…”

“…As the interacting v 4 = 1 and v 5 = 2 levels are only 9.694 cm À1 When no parentheses are shown the value is constrained to ground state values from Ref. [21]. b F i,j and F Ji,j are the zero order and J-dependent Fermi terms, respectively, defined by hi; J ; K a ; K c jĤjj; J ; K a ; K c i ¼ F i;j þ J ðJ þ 1ÞF Ji;j .…”

“…Even though no m 5 + m 6 band transitions were identified, treatment of the perturbations and avoided crossings in m 2 permitted Joo and Clouthier to obtain the band origin and a set of rotational constants for the dark v 5 = 1, m 6 = 1 state [20]. An analysis of the NAS stretching (m 3 ) and NSO bending (m 5 ) fundamentals was reported using high-resolution FTIR spectroscopy [21]. An improved set of ground state rotational constants was obtained along with excited vibrational state constants for both bands, neither of which exhibited any perturbations.…”