The analysis of combination and overtone states of 11BF3 from 1650 to 4600cm−1

On the determination of C0 (or A0), , and some dark states for symmetric-top molecules from infrared spectra without the need for localized perturbations

“…2 we show a second example drawn from the observed transitions in both BF 3 [17][18][19] and SO 3 [20]. This example uses the allowed Dk = ±1, Dl = Ç2 transitions from the ground state to the (001 1 1 1 ) 2 state and the hot band transition (001 1 1 1 ) 2 À 000 0 1 1 with the selection rules Dk = ±1 and Dl = ±1 in combination with the m 4 transition 000 0 1 1 À 000 0 0 0 which also has the selection rules Dk = ±1 and Dl = ±1.…”

“…(2) H KJ 0 Â 10 12 3.31 (7) 3.25 (3) H K 0 Â 10 12 À1.32(4) À1.28 ( In the case of BF 3 the m 1 level is not accessible as an allowed transition from the ground state, but is observed as a difference band with either m 3 or 2m 3 as the upper state. Although the m 1 vibrational level is at about 885 cm À1 the difference bands, either m 3 À m 1 or 2m 3 À m 1 , are easy to observe if one has access to a long path absorption cell [17][18][19][20][21].…”

An approach for the description of vibrational excitations: Application to 11BF3

“…Recently in a series of works the high resolution infrared and Raman spectra of 11 BF 3 from 400 to 4600 cm À1 has been analyzed [48][49][50][51][52]. Previous investigations in this region had already been performed, although at a moderate resolution [53].…”

“…The equilibrium configuration of the 11 BF 3 molecule is D 3h planar with structure parameter r e = 1.3070 Å [52]. Since the dipole operator spans the A 00 2 and E 0 representations only the m 1 vibrational mode is infrared inactive, the other three fundamentals are infrared active.…”

Analysis of the high-resolution infrared spectrum of cyclopropane

“…The conventions and nomenclature for the various matrix elements and rovibrational constants are the same as that described in previous work by the authors on both 10 BF 3 and 11 BF 3 [20][21][22][23] and a variety of SO 3 isotopomers [17,[24][25][26][27]. Because cyclopropane has several normal vibrational modes, we are using in many places the Brand, Callomon, Watson (BCW) symbolism for denoting the vibrational states and transitions [28][29][30].…”