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从分子动力学原理出发,提出了外场作用下的解吸动力学模型,分析讨论了超声场强化解吸速率的机理及超声场与吸附相分子振动之间的协同作用。根据超声条件下吸附相分子的受迫振动和非吸附相分子的波动,分别讨论了吸附相分子及非吸附相分子在超声波场中获得的能量并进行了数量级分析和比较。结果表明,在超声波场中吸附相分子比非吸附相分子获得更多的能量,一般要大10个数量级以上,这正是超声波场强化解吸速率的本质所在。进一步理论分析表明,对一定频率的超声波,能流越大解吸速率越大,这是与实验相符的;同时,在超声波能流一定的情况下,可使超声波频率达到吸附相分子的固有频率而使解吸速率强化,这是超声波场与吸附相分子振动之间协同的结果。
Based on the principle of molecular dynamics, a kinetic model of desorption under external field was proposed. The mechanism of the enhanced desorption rate of ultrasonic field and the synergy between ultrasonic field and molecular vibration of adsorbed phase were analyzed. According to the forced vibration of adsorbed molecules under ultrasonic conditions and the fluctuation of non-adsorbed molecules, the energies of adsorbed molecules and non-adsorbed molecules in the ultrasonic field were discussed and analyzed and compared in order of magnitude. The results show that it is generally 10 orders of magnitude larger to obtain more energy in the ultrasonic field than the non-adsorbed molecules, which is exactly the nature of the field-enhanced desorption rate. Further theoretical analysis shows that for a certain frequency of ultrasonic wave, the larger the energy flow, the larger the desorption rate, which is consistent with the experiment. At the same time, under the certain ultrasonic energy flow, the ultrasonic frequency can reach the natural frequency of the adsorbed phase molecule The desorption rate is enhanced, which is the result of the synergy between the ultrasonic field and the molecular vibration of the adsorbed phase.