Production and characterization of para-hydrogen gas for matrix isolation infrared spectroscopy

• Design, development and fabrication of the ortho–para converter.
• Para-H2 characterized using infrared and Raman spectroscopic techniques.
• The purity of p-H2 found to be >99%.
• Infrared spectra of trimethylphosphate and acetylene studied in p-H2 matrix.

Normal hydrogen (n-H2) has 3:1 ortho/para ratio and the production of enriched para-hydrogen (p-H2) from normal hydrogen is useful for many applications including matrix isolation experiments. In this paper, we describe the design, development and fabrication of the ortho-para converter that is capable of producing enriched p-H2. The p-H2 thus produced was probed using infrared and Raman techniques. Using infrared measurement, the thickness and the purity of the p-H2 matrix were determined. The purity of p-H2 was determined to be >99%. Matrix isolation infrared spectra of trimethylphosphate (TMP) and acetylene (C2H2) were studied in p-H2 and n-H2 matrices and the results were compared with the conventional inert matrices.