Help Privacy Policy Disclaimer
  Advanced SearchBrowse


  Diffuse reflectance IR study of molecular hydrogen and deuterium adsorbed at 77 K on NaA zeolite. Part 1.-Fundamentals, combination and vibrational–rotational modes

Kazansky, V. B., Borovkov, V. Y., & Karge, H. G. (1997). Diffuse reflectance IR study of molecular hydrogen and deuterium adsorbed at 77 K on NaA zeolite. Part 1.-Fundamentals, combination and vibrational–rotational modes. Journal of the Chemical Society, Faraday Transactions, 93(9), 1843-1848. doi:10.1039/A700079K.

Item is


show Files




Kazansky, Vladimir B.1, Author
Borovkov, Victor Yu.1, Author
Karge, Hellmut G.2, Author           
1Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences, Leninsky Prospect 47, Moscow, B-334 Russia, ou_persistent22              
2Fritz Haber Institute, Max Planck Society, ou_24021              


Free keywords: -
 Abstract: The adsorption of hydrogen and deuterium on the sodium form of zeolite A at 77 K has been investigated by diffuse reflectance FTIR (DRIFT) spectroscopy. The spectra exhibited bands of stretching vibrations which appeared because of the disturbance of the homonuclear diatomic molecules in the electric field of the adsorption sites (cations). These bands were detected at 4088 and 2939 cm−1 for hydrogen and deuterium, respectively. A correlation between the amount of adsorbed molecules and the increase in the intensity of the IR signal as a function of equilibrium pressure under isothermal conditions was found. This indicates that, at low pressures, only the interaction with the cations is relevant for H2 or D2 adsorption in NaA at 77 K and non-specific physical adsorption is negligible. Moreover, satellites of the main bands and weaker high-frequency features were observed. The positions of both the main stretching vibration bands and the satellites depended on the pressure of the adsorbate. It is suggested that, at lower pressures, sodium cations located in the eight-membered rings were involved as sites of higher adsorption potential, whereas at higher pressures weaker adsorption occurred on sodium cations residing in the six-membered rings of the framework. Stronger adsorption was indicated by a higher separation of the satellites from the main bands, viz. 93 cm−1 (H2) and 75 cm−1 (D2) cf. 56 cm−1 (H2) and 40 cm−1 (D2) for weaker adsorption at higher pressures. It is proposed that the satellites appear owing to a combination of the stretching vibration mode of the molecular bonds of H2 or D2 with an oscillation of the whole molecule against the adsorption site. Several weaker signals were observed at higher frequencies separated by 288 and 495–570 cm−1 (H2) or ca. 173 and ca. 400 cm−1 (D2) from the main stretching bands. These were interpreted as features arising from vibrational–rotational transitions of the ortho- and para-forms of H2 or D2. Comparison of the above frequency data with the simple model for rotational energy levels of diatomic molecules suggests that the rotation of H2 and D2 molecules adsorbed on NaA zeolite is to some extent hindered.


Language(s): eng - English
 Dates: 1997-01-01
 Publication Status: Issued
 Pages: 6
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.1039/A700079K
 Degree: -



Legal Case


Project information


Source 1

Title: Journal of the Chemical Society, Faraday Transactions
  Other : J. Chem. Soc., Faraday Trans.
Source Genre: Journal
Publ. Info: Cambridge, UK : The Society
Pages: 6 Volume / Issue: 93 (9) Sequence Number: - Start / End Page: 1843 - 1848 Identifier: ISSN: 0956-5000
CoNE: https://pure.mpg.de/cone/journals/resource/954925272413