What are the differences between the triplet and singlet states. triplet state-- parallel spins-- S=1 , 2S+1=3 Singlet state-- Paired spins---S=0 , 2S=1= 1 singlet state has paired spins of electrons in the same orbit, thus there are repulsion force between the two electron in the same orbit. Thus, singlet state is in higher energy than triplet state. Apart than this, is there any differences between singlet state and triplet state? For instance, the population, half life, solvent effect and etc.