Molar Entropy and Enthalpy of CO Adsorbed in Zeolites as Derived from VTIR Data: Role of Intermolecular Modes.

Detailed analysis of recently reported variable-temperature IR (VTIR) spectra of carbon monoxide adsorbed in alkaline zeolites shows how, not only the corresponding values of standard adsorption enthalpy ( Δ H 0 ) and entropy ( Δ S 0 ) can be obtained, but also the thermodynamic values of molar entropy and enthalpy which characterize the adsorbed gas phase. In addition, it is shown that the so obtained molar entropy data can lead to new insights into soft molecular modes, which would be hardly accessible by conventional IR spectroscopic techniques.