Real microstates change within mixing two gases

1. sludger13

83
Hello,
I'm looking for some changes of energy states of particles, as two gases are mixing together without total volume changing. That would explain increasing entropy better than their position combination.
I know the particle energy states are getting more closely (the band gaps are reducing) as the gas is expanding. Is this the same effect?
Thanks for every remark or advice.

Last edited: Dec 31, 2013
2. sludger13

83
I think I found the answer - it is the same phenomenon like a gas expansion.
Though I don't get it, why that band gap decreasing should happen during expansion.