Determination of dissociation energies and thermal functions of hydrogen-bond formation using high resolution FTIR spectroscopy

A technique which employs high resolution Fourier transform infrared spectroscopy is demonstrated for evaluation of hydrogen bond dissociation energies D0 and De. Results for HCN‐‐HF give a D0=20.77(22) and De =28.77(45) kJ/mol which are compared with previously determined values obtained from microwave absolute intensity measurements and ab initio molecular orbital calculations. Rovibrational band information available for HCN‐‐HF also permits evaluation of thermal functions of dimer formation in kJ/mol: ΔU○298.2 =20.1(2), ΔH○298.2 =22.6(2), ΔG○298.2 =59.4(2), ΔS○298.2 =−0.1235.

[1]  Roger Hayward,et al.  The Hydrogen Bond , 1960 .

[2]  R. Lord.  Vibrational spectra and structure : Volume 7, J.R. Durig, ed., Elsevier Scientific Publishing Co., Amsterdam, 1978, xv + 388 pages. Dfl. 146,00, $63.50. , 1976 .

[3]  K. Rao,et al.  Vibration rotation bands of heated hydrogen halides , 1968 .

[4]  B. A. Wofford,et al.  Predissociating fundamental vibrations of DCN‐‐‐DF , 1987 .

[5]  Anthony C. Legon,et al.  Experimental determination of the dissociation energies D0 and De of H2O…HF , 1987 .

[6]  C. E. Dykstra,et al.  Changes in the electronic structure and vibrational potential of hydrogen fluoride upon dimerization: A well‐correlated (HF)2 potential energy surface , 1984 .

[7]  B. A. Wofford,et al.  Molecular dynamics in hydrogen‐bonded interactions: A preliminary experimentally determined harmonic stretching force field for HCN‐‐‐HF , 1987 .

[8]  W. J. Lafferty,et al.  Rovibrational analysis of the v15 band in the HCN---HF hydrogen bonded cluster , 1986 .

[9]  W. J. Lafferty,et al.  Rovibrational analysis of an intermolecular hydrogen‐bonded vibration: The ν16 band of HCN‐‐‐HF , 1986 .

[10]  C. E. Dykstra,et al.  The nature of hydrogen bonding in the NN–HF, OC–HF, and HCN–HF complexes , 1983 .

[11]  D. Millen,et al.  Dissociation energies of the hydrogen‐bonded dimers RCN⋅⋅⋅HF (R=CH3, HCC) determined by rotational spectroscopy , 1987 .

[12]  G. Herzberg,et al.  Infrared and Raman spectra of polyatomic molecules , 1946 .

[13]  R. Toth.  Wavenumbers, strengths, and self-broadened widths of CO2 at 3 μm , 1974 .

[14]  T. A. Wiggins,et al.  Highly Precise Wavelengths in the Infrared. II. HCN, N 2 O, and CO† , 1961 .

[15]  Alan S. Pine,et al.  Hydrogen bond energies of the HF and HCl dimers from absolute infrared intensities , 1986 .

[16]  S. C. Rogers,et al.  Spectroscopic investigations of hydrogen bonding interactions in the gas phase. I. The determination of the geometry, dissociation energy, potential constants and electric dipole moment of the hydrogen-bonded heterodimer HCN • • • HF from its microwave rotational spectrum , 1980, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[17]  D. R. Stull.  JANAF thermochemical tables , 1966 .

[18]  C. Sandorfy.  Vibrational spectra of hydrogen bonded systems in the gas phase , 1984 .

[19]  S. C. Rogers,et al.  A method for the determination of the dissociation energies D0 and De for hydrogen-bonded dimers from the intensities of rotational transitions and its application to HCN…HF , 1978 .