When heavy negative particles ( ) are stopped in matter they usually form exotic atoms in highly excited states. The exotic atom formation is followed by an atomic cascade consisting of multistep transition to the lower atomic states. Despite a long history of theoretical and experimental studies the kinetics of this atomic cascade is not fully understood. However, new generation of experiments involving problems which need more knowledge about cascade transitions. Kaonic helium atom is formed in highly excited state when kaons are stopped in helium. The cascade transition rates of this atom because of many complexities were usually calculated by using semi type="#_x0000_t75" atom is calculated by using full quantum mechanical approaches. The obtained results have been used in a parallel work for calculation of X-ray yields, kaon absorption fraction from each atomic state and etc… Also, in this thesis some aspect of atom with respect to and atoms has been studied