Modeling resonator frequency fluctuations induced by adsorbing and desorbing surface molecules
Modeling resonator frequency fluctuations induced by adsorbing and desorbing surface molecules
复制标题
模拟吸附和解吸表面分子引起的谐振器频率波动
DOI：
10.1109/58.63111
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
J. Vig
中科院分区：
文献类型：
--
作者：
Yook;J. Vig
利用吸附分子的质量负载效应原理，研究了分子在平板电极上吸附和脱附引起的共振频率起伏。这项研究是基于一个525 MHz，AT切石英谐振器封闭在一个小的晶体保持器。导出了晶体保持器表面吸附速率与压力的关系式，发现吸附速率是二次多项式函数。基于这些方程的计算表明，当温度变化时，具有较高解吸能量的污染物气体产生较大的压力变化。由于任何一个污染站点的频率波动的功能描述是一个连续时间的马尔可夫链。推导了马尔可夫链的Kolmogorov方程和自相关函数。导出了谐振腔频率起伏的自相关函数和谱密度函数。在1 Hz的频率波动的谱密度作为压力，温度和分子的解吸能量的函数进行了研究。发现具有一种类型的分子的污染物气体的噪声水平对于较低的解吸能量是较低的，并且在较低的压力下是较高的。<<ETX>>
Resonator frequency fluctuations due to adsorption and desorption of molecules on plate electrodes are studied using the principle of mass-loading effects of adsorbed molecules. The study is based on a 525 MHz, AT-cut quartz resonator enclosed in a small crystal holder. Equations relating the surface adsorption rates of the crystal holder to pressure were derived and found to be quadratic polynomial functions of the adsorption rates. Calculations based on these equations show that a contaminant gas with a higher desorption energy creates larger changes in pressure when the temperature is varied. The function describing the frequency fluctuations due to any one contaminant site is a continuous-time Markov chain. Kolmogorov equations and an autocorrelation function for the Markov chain are derived. The autocorrelation and spectral density function of resonator frequency fluctuations are derived. The spectral density of frequency fluctuations at 1 Hz is studied as a function of pressure, temperature, and desorption energy of molecules. The noise levels for a contaminant gas with one type of molecules are found to be lower for lower desorption energies, and higher at lower pressures.<<ETX>>