Hyperfine constants of bromine and iodine monofluoride

Abstract

The JЈϪJЉϭ1Ϫ0 rotational transitions of 79 BrF, 81 BrF, and IF have been reinvestigated in the ground and first excited vibrational states using microwave Fourier transform spectroscopy. For IF, lines were also detected in the second excited vibrational state. Bromine and iodine nuclear quadrupole coupling constants, spin-rotation constants for all nuclei, and tensor and scalar spinspin coupling constants ͑S and J͒, have been determined along with the rotational constants. Antishielding occurs at the fluorine nucleus for both BrF and IF, as has been found earlier for ClF. The antishielding has been rationalized following a model developed for ClF. The ratio 1.197 0514 ͑32͒ has been found for the equilibrium bromine quadrupole coupling constants of 79/81 BrF.

Assignment and analysis of the rotational spectrum of bromoform enabled by broadband FTMW spectroscopy

“…The v yy values for a given isotopic bromine nucleus should thus be identical in all species containing such a nucleus. This is indeed found to be the case, as for 79 Br in HCBr 3 , for example, v yy is equal to À311.892(5), À311.895 (6) [40]. We note, however, that the present ground state values are not sufficiently precise to discern any averaging effects relative to the equilibrium values in [39,40], since such effects have been found to be at the level of 3 Â 10 À6 [40].…”

“…This is indeed found to be the case, as for 79 Br in HCBr 3 , for example, v yy is equal to À311.892(5), À311.895 (6) [40]. We note, however, that the present ground state values are not sufficiently precise to discern any averaging effects relative to the equilibrium values in [39,40], since such effects have been found to be at the level of 3 Â 10 À6 [40]. Furthermore, the very small isotopic rotation of bromoform in its inertial frame on bromine substitution is well reflected by changes in the precisely determined quadrupolar angles.…”

Fourier transform microwave spectroscopy of aluminum hydrosulfide, AlSH

“…In general, C ðAlÞ I can be written as the sum of two parts [39][40][41]: C nucl I is the nuclear part, and depends only on the positions of the nuclei. For a linear molecule, it is given by:…”

The rotational spectrum and hyperfine structure of arsenic monophosphide, AsP

“…The nuclear spin-rotation coupling constants C I (As) and C I (P) have been used to calculate the shieldings for Table 6 Comparison of the non-phosphorus nuclear quadrupole coupling constants of the Group both nuclei. For a diatomic molecule C I can be expressed as the sum of nuclear and electronic contributions [35,36] …”