Theoretical study of slowing supersonic CH₃F molecular beams using electrostatic Stark decelerator

We have calculated the Stark effect of CH₃F molecules in external electrical fields, the rotational population of supersonic CH₃F molecules in different quantum states, and analyse the motion of weak-field-seeking CH₃F molecules in a state |J=1, KM= -1\rangle inside the electrical field of a Stark decelerator by using a simple analytical model. Three-dimensional Monte Carlo simulation is performed to simulate the dynamical slowing process of molecules through the decelerator, and the results are compared with those obtained from the analytical model, including the phase stability, slowing efficiency as well as the translational temperature of the slowed molecular packet. Our study shows that with a modest dipole moment (～1.85 Debye) and a relatively slight molecular weight (～34.03), CH₃F molecules in a state |J=1, KM= -1\rangle are a good candidate for slowing with electrostatic field. With high voltages of ±10 kV applied on the decelerator, molecules of 370 m/s can be brought to a standstill within 200 slowing stages.