Analysis of high-resolution infrared and CARS spectra of 32S18O3

Abstract

As part of a series of investigations of isotopic forms of sulfur trioxide, high-resolution infrared and coherent anti-Stokes Raman spectroscopies were used to study the fundamental modes and several hot bands of 32 S 18 O 3 . Upper levels of hot bands originating from the m 2 and m 4 bending mode states have been found to couple strongly to the upper levels of the IR-inactive m 1 symmetric stretch through indirect Coriolis interactions and Fermi resonances. Coriolis coupling effects are particularly noticeable in 32 S 18 O 3 due to the close proximity of the m 2 and m 4 fundamental vibrations, whose deperturbed wavenumber values are 486.48813(4) and 504.28477(4) cm À1 . The uncertainties in the last digits are shown in parentheses and are two standard deviations. From the infrared transitions, accurate rovibrational constants are deduced for all of the mixed states, leading to deperturbed values for m 1 , a B 1 , and a C 1 of 1004.68(2), 0.000713(2), and 0.000348(2) cm À1 , respectively. The B e value is found to be 0.310820(2) cm À1 , yielding an equilibrium bond length r e of 141.7333(4) pm that is, within experimental uncertainty, identical to the value of 141.7339(3) pm reported previously for 34 S 18 O 3 . With this work, precise and accurate spectroscopic constants have now been determined in a systematic and consistent manner for all the fundamental vibrational modes of the sulfur trioxide D

The high-resolution infrared spectrum of 11BF3 from 400 to 1650cm−1

“…The nomenclature and conventions used throughout this work are the same as those described in previous work by the authors on 10 BF 3 [16] and a variety of SO 3 isotopomers [23][24][25][26][27][28][29][30][31]. It is also consistent with an earlier study of BF 3 by Zeisberger and Ruoff [32,33], with the exception of the splitting constants t v and D v which are smaller by a factor of two in this work.…”

“…[36]. The form of the Hamiltonian used in this analysis was also effectively applied in work on 10 BF 3 [16] and in the study of various SO 3 isotopomers [23][24][25][26][27][28][29][30][31]. We give here the final forms for each of the diagonal and off-diagonal interaction terms used in fitting all the transitions assigned in this work.…”

“…The observed transition wavenumbers were fit using a least-squares fitting program, similar to the one used in the analysis of SO 3 [23][24][25][26][27][28][29][30][31], though modified to be more generally applicable. Specific information regarding the number and extent of transitions fit for the individual bands together with their band origins and rms deviations can be found in Table 3.…”

Coherent Raman spectra of the ν1 mode of 10BF3 and 11BF3

“…Four fundamental vibrational modes occur for both molecules, of symmetry species C ¼ A 0 1 ðRÞ þ A 00 2 ðIRÞ þ 2E 0 ðIR; RÞ. All four fundamental transition frequencies have been deduced for 32 S 16 [1][2][3][4][5][6][7][8][9], along with many transitions to combination or overtone states. Special interest has focused on the m 1 symmetric stretching mode which can only be seen directly by Raman methods but whose transition frequency has been deduced from infrared active hot-bands and differencebands.…”

“…In a recent series of papers [1][2][3][4][5][6][7][8][9][10][11], we have used high resolution infrared and coherent Raman methods to examine the spectroscopic properties of sulfur trioxide and boron trifluoride. Both molecules are classic examples of a planar symmetric top of D 3h symmetry.…”