Differences between the triplet and singlet states

[Cheminewbie]

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.

 

[hilbert2]

For example, singlet O₂ is a lot more reactive than normal triplet O₂ and reacts with water to form hydrogen peroxide. Look it up in wikipedia http://en.wikipedia.org/wiki/Singlet_oxygen .

I'm not sure about other elements, maybe someone else knows more.

 

[Einstein Mcfly]

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.

Your conclusion is not general. It's not always the case that singlet spin multiplicity is higher in energy than a triplet. The things you listed all depend on the particular case.

 

[gravenewworld]

Half lives from triplet to ground state are longer than singlet to ground state transitions. This is of HUGE importance in fluorescence microscopy.