The spin-orbit coupling parts in the effective one-electron Hamiltonian operator, with the inclusion of symmetry, have been used to formulate mechanisms based on the Shaik and Epiotis theory in tripler reactions for the radiationless decay of tripler complexes to singlet ground state products. This has been applied to investigate the stereochemical behavior of additions of triplet carbenes to olefins. It is shown that tripler carbene-olefin complexes can be classified according to the number and the direction of the atomic orbital rotations required to maximize spin-orbit coupling and simultaneously maintain the intermolecular binding, from which it may produce different stereoisomers. It is suggested that six spin-inversion reaction mechanisms produce geometric isomers. It is found that, as a direct of the different symmetries of the three sublevels of the triplet state (T-x, T-y, T-z) and their comparable spin-orbit coupling expressions, the tripler carbene could add to olefins nonstereospecifically. Nevertheless, it is also suggested that, because of its larger spin-orbit coupling expression as well as the less conformational change, the cycloaddition of a triplet carbene to a double bond will lead tb the stereospecific cyclopropane with retention of geometry in a concerted pathway. The solvent polarity, substituent effect, and heavy atom effect must all play an important role in determining the stereoconformations of adducts. The results obtained are in agreement with the available experimental results and allow a number of predictions to be made. It is found that the approach proposed in this study is proved to be a good alternative to the traditionally accepted explanation, the Skell-Woodworth mechanism.