RT Journal Article
SR Electronic
T1 Hydrogen bonding in the vapour phase between water and hydrogen fluoride: the infrared spectrum of the 1:1 complex
JF Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences
JO Proc R Soc Lond A Math Phys Sci
FD The Royal Society
SP 579
OP 592
DO 10.1098/rspa.1975.0120
VO 344
IS 1639
A1
YR 1975
UL http://rspa.royalsocietypublishing.org/content/344/1639/579.abstract
AB The infrared spectrum of the 1:1 complex in the vapour phase between water and hydrogen fluoride has been observed for the first time, and measured over the range 4000-400 cm-1. Three bands of the complex have been observed, one associated with the stretching vibration of HF, one with the bending of the water molecule, and the other with two bending vibrations of the hydrogen bond itself. The first band shows that HF forms the hydrogen bond. Interpretation of its fine structure gives the frequencies of two bending vibrations at 145 and 170 cm-1. The structure of the band associated with the two bending vibrations at about 700 cm-1 has been tentatively analysed to show th at the complex is planar (C2v) and to give a value of the Coriolis constant for the interaction of the two vibrations. The value of this constant shows th at either the bending force field has an unusually large interaction force constant or one of the vibrations is anharmonic. W ith the help of an estimated value of the only remaining unknown vibration frequency of the complex, that of the intermolecular stretching vibration at 180 cm-1, the bending vibration frequencies above, and an estimate of the extinction coefficient of the band associated with the HF stretch, the enthalpy of the association of water and hydrogen fluoride is calculated to be — 26 kJ mol-1 at just above room temperature. From this a value of the potential energy well depth for the interaction has been found to be — 30 kJ mol-1.