Experimental generation of a cw cold CH(3)CN molecular beam by a low-pass energy filtering.
Experimental generation of a cw cold CH(3)CN molecular beam by a low-pass energy filtering.
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DOI：
10.1039/b913929j
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发表时间：
2010-01
期刊：
影响因子：
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通讯作者：
Yang Liu;Min Yun;Yong Xia;L. Deng;J. Yin
中科院分区：
文献类型：
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作者：
Yang Liu;Min Yun;Yong Xia;L. Deng;J. Yin
我们利用L形弯曲四极静电波导（即，采用低通能量或速度滤波），并利用光电离飞行时间质谱仪方法，实验测量和研究了被导引CH（3）CN束的纵向和横向温度以及导引效率与导引电压的关系。我们发现了一个新的比例定律：被引导的CH（3）CN束的纵向和横向温度（T（z），T（ρ））与引导电压成正比（T（z），T（ρ）与V（guide）成正比），并进一步验证了另一个标度律：分子引导效率η与引导电压的平方成正比（η与V2（guide）成正比）。我们还得到了一些与我们的实验结果一致的模拟结果。我们还测量了输出分子束的发散角，并研究了它对引导电压的依赖关系。研究表明，当导向电压为V（guide）= +/-1kV时，利用L型静电导向器可以产生纵向温度约为500 mK，横向温度约为40 mK的连续波冷CH（3）CN束。当V（guide）= +/-4kV时，输出CH（3）CN光束的发散角约为16.4 °。由此产生的冷分子束在冷分子物理、物理化学和化学物理等领域有着重要的应用。
We generate a continuous-wave (cw) cold methyl cyanide (CH(3)CN) beam by using an L-shaped bent quadrupole electrostatic guide (i.e., by a low-pass energy or velocity filtering), and use a photo-ionized time-of-flight mass-spectrometer method to experimentally measure and study the dependences of the longitudinal and transverse temperatures of the guided CH(3)CN beam and its guiding efficiency on the guiding voltage. We find a new scaling law: the longitudinal and transverse temperatures (T(z),T(rho)) of the guided CH(3)CN beam are proportional to the guiding voltage (T(z),T(rho) proportional to V(guide)), and further verify another scaling law: the molecular guiding efficiency eta is proportional to the square of the guiding voltage (eta proportional to V2(guide)). We also obtain some simulated results consistent with our experimental ones. We also measure the divergent angle of the output molecular beam and study its dependence on the guiding voltage. Our study shows that when the guiding voltage is V(guide) = +/-1 kV, a cw cold CH(3)CN beam with a longitudinal temperature of approximately 500 mK and a transverse one of approximately 40 mK can be generated by our L-shaped electrostatic guide. The divergent angle of the output CH(3)CN beam is about 16.4 degrees as V(guide) = +/-4 kV. It is clear that such a resulting cold molecular beam has some important applications in the fields of cold molecular physics, physical chemistry and chemical physics, etc.