Studies on Hydrogen–Oxygen Systems in the Electrical Discharge. V. Raman Spectra of the Trapped Products

Abstract

The condensed products (at – 180 °C) of electrically dissociated water vapor and other related systems were examined by means of laser Raman spectroscopy. A new type of total reflection cell had to be developed for the study of metastable species trapped in an amorphous matrix. Besides the characteristic O—O stretching band of hydrogen peroxide at 878 cm−1, always the strongest, another fairly strong band at 500 cm−1, and a third one at about 760 cm−1 were present in all cases. A couple of weaker bands around 820–830 cm−1 and 430–440 cm−1 occurred only in oxygen-rich system (H2O2 vapor or H2O–O2 mixtures). In the latter, the presence of condensed ozone was confirmed by a band at 1025 cm−1, and occasionally another faint one around 1120 cm−1.The relative intensities of the bands varied locally in a given sample, indicating uneven composition.Isotopic shifts with 18O confirmed that these Raman bands arise from vibrations of oxygen atoms. Essentially the same results were obtained in hydrogen as in deuterium systems, except that in the latter case the new bands were appreciably stronger and sharper. The present results support the assignment of previous infrared spectra to hydrogen polyoxides, H2O3 and H2O4.