Theoretical Study On Stark Deceleration Of CH Molecules And The Electric Field Measurement

Cold molecules have some important applications in high-resolution spectroscopy and precise measurement, study of cold chemical reaction and cold collisions, interferometer of matter wave, and quantum computing and information possessing and so on. In recent years, study on the generation and application of cold molecules has obtained fast development. So far, there have been two major methods to produce cold molecules, in the first method, cold molecules are produced by photo association spectrum and Feshbach resonance technique from cold atoms that are produced by laser cooling, in the second method, and cold molecules are produced from hot and chemical steady molecules. These methods contains buff gas cooling, AC Stark deceleration and low energy filter and so on. In this thesis, the principle, experiment and recent progress on cooling, trapping and manipulating of neutral molecules are first briefly introduced and reviewed. Second, we show the theoretical study for the CH molecules Stark deceleration and the electric field measurement. Finally, our research work is summarized and the future investigation is briefly looked ahead.We propose a new scheme to realize CH molecules Stark deceleration, and calculate the Stark splitting of CH molecules in the electric field and the population of CH molecules in different rotational states, and then we perform Monte-Carlo simulations for dynamic process of CH Stark deceleration under different experiment conditions, and obtain some optimal parameters. Our study shows that the longitudinal velocity of CH radicals can be decelerated to 24m/s using 119 stages, and the velocity spread (full width of half maximum) of the decelerated molecules is 4.2m/s, corresponding to a traverse temperature of 27mK, the number of cold molecules in the decelerated package is about 1% of initial molecular number.We also propose a novel electrostatic field measurement scheme by using the Stark effect of neutral NO molecules, and calculate the Stark splitting of NO molecules in the electric field and the population of rotational states at the room temperature, and analyze the relation between the sensibility of the electric field measurement and system parameters. In final, we discuss some main factors to influence the measurement of electrostatic field and some ways to reduce the experimental errors.