The Theoretical Study On Photostop Of Iodine Atoms From Electrically Oriented IC1 Molecules

This thesis firstly studies the energy level shifts and orientational probability distributions (OPD) of three types of cold molecules including the linear, the symmetric top and the asymmetric top ones under electrostatic fields. The avoided crossings of quantum states of molecules exposed to strong electrical fields are also investigated. Then, theoretical studies on photostopping iodine atoms from electrically oriented ICl molecules and their magnetic trapping are carried out.Matrix method is adopted for investigating the energy level shifts and OPD of molecules exposed to strong electrical fields, since perturbation theory fails. Corresponding results are obtained by diagonalizing the Hamiltonian matrix of molecules formed on an appropriate basis set.The dynamics of photostopping iodine atoms from electrically oriented ICl molecules is numerically studied based on their orientational probability distribution functions (OPDF). Velocity distributions of the iodine atoms and their production rates are investigated for orienting electrical fields of various intensities. For the ICl precursor beams with an initial rotational temperature of ～1K, the production of the iodine atoms near zero speed will be improved by about ～5 times when an orienting electrical field of ～200kV/cm is present. A production rate of ～0.5%o is obtained for photostopped iodine atoms with speeds less than lOm/s, which are suitable for magnetic trapping. The electrical orientation of ICl precursors and magnetic trapping of photostopped iodine atoms in situ can be conveniently realized with a pair of charged ring magnets. Trajectory Simulations indicate that the relative number of the magnetically trapped iodine atoms, compared to the initial number of ICl precursors exposed to an orienting electrical field of ～100kV/cm, is on the order of ～5×10-5 when the maximal value of the trapping field is about ～0.28T, corresponding to the largest trapping speed of ～7.0m/s for the iodine atom.