Resonant Transmission through Double Quantum Dots: Model and Numerical   Results
  Via projection operator technology, we restrict our discussion of Double Quantum Dots system in subspaces of fixed electron population. When an incident electron tries to pass through the dots, we find transmission peaks occur, if the system energy scans through eigen-levels in one-more-electron higher subspace of the dots. Also, we find some selection rules for this resonant transmission. We attribute some of these rules to the differences between many-electron bonding states and anti-bonding states. 
Yuhui He, Qin-Wei Shi