ACCURATE MEASUREMENT OF VIBRATIONAL TRANSITION ENERGIES FOR A WIDE RANGE OF v, J STATES USING CARS SPECTROSCOPY OF CHEMICAL REACTION PRODUCTS: SPECTROSCOPY OF H2 FROM THE H + HI REACTION

Article abstract of DOI:10.1021/j100324a022

Q_v(J) transition energies of H2 are measured for v = 0-4, J = 0-18 by coherent anti-Stokes Raman scattering (CARS) spectroscopy of rovibrationally excited H2 from the H + HI <*> H2 + I reaction at high collision energies.The accuracy of the measurements reported here is 0.05 cm^-1, limited by the bandwidth of the laser sources used.The measured transition energies generally agree with those predicted by ab initio quantum calculations and with previous less precise maesurements based on H2 electronic spectroscopy.However, discrepancies outside mutual uncertainties are common, and the accuracy of the ab initio calculations appears to besomewhat less than the 0.015 cm^-1 claimed.Measurements with an accuracy of 0.0005 cm^-1, much greater than that of the present measurements, are possible with the methods described here by using narrow-bandwidth laser sources for CARS spectroscopy.