Pierce oscillator

A sdiematic of our experimental setup is shown in Fig. 1. Isotherms are recorded by monitoring adsorption onto metal electrodes which we have evaporated onto the major surfaces of a quartz crystal oscillator which vibrates in a transverse-shear mode. The crystal is driven at its resonant frequency by means of a Pierce oscillator circuit (ref. 13). Changes in frequency are proportional to the quantity of gas adsorbed (ref. 14), so an isotherm is a plot of frequency shift versus pressure at fixed temperature. The microbalance crystals for these studies were polished single crystals of quartz which had quality factors near 10 (ref. 15). We produced the electrodes by evaporation of 99.999% pure Ag or Au at 5 X 10 torr onto the faces of the quartz blanks. The temperature of the substrate was variable between 80 and 500 K. The deposition rate was variable between. 5 and 76 A/s. 

Gordon ( ) has calculated the thermodynamic functions from 298.15 to 6000 K by the method of Pennington and Kobe (4) which takes vibration-rotation interaction and anharmonicity into account. Gordon s data are from Pierce (5). The functions below 298.15 K have been calculated for a rigidly rotating harmonic oscillator ... 

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