Hydrogen adsorbed glass

An interesting point is that infrared absorptions that are symmetry-forbidden and hence that do not appear in the spectrum of the gaseous molecule may appear when that molecule is adsorbed. Thus Sheppard and Yates [74] found that normally forbidden bands could be detected in the case of methane and hydrogen adsorbed on glass this meant that there was a decrease in molecular symmetry. In the case of the methane, it appeared from the band shapes that some reduction in rotational degrees of freedom had occurred. Figure XVII-16 shows the IR spectrum for a physisorbed H2 system, and Refs. 69 and 75 give the IR spectra for adsorbed N2 (on Ni) and O2 (in a zeolite), respectively. 

In order to have localized adsorption with only physical interaction it is clear that either the interaction must be strong, or the kinetic energy of the adsorbed molecules must be small. As an example of the latter condition we have the work of Keesom and Schweers (24, 25) for low temperature adsorption of hydrogen and neon on glass. They assumed that the actual area of the glass was equal to the apparent area, and the results in Table IX were worked out for = 3 on that basis. The... 

Enzymes can be adsorbed on various types of materials e.g. silica gel, metal oxides, glass and organic polymers. Depending on the natnre of the carrier material, adsorption can be accomplished by hydrogen bonding hydrophobic interaction and ionic forces. 

It is evident from the data presented that ultraviolet light has different and more specific effects on forming radicals in polyolefins than those previously found for ionizing radiation. Furthermore, hydrogen atoms have been observed in the ESR spectra from ultraviolet experiments (6, 24). The hydrogen radicals, however, are not believed to be located in the polymer matrix but to be formed in the glass or adsorbed on the glass surface of the sample cell (6). 

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