Shape resonance in electron- atom and electron-molecule molecule collision:
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Complex absorbing potential based coupled-cluster theory
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Electron-atom and electron-molecule  shape resonance leads to metastable
resonant states, which become unnormalizable. Thus, bound state quantum
chemistry techniques can not be applied. However, using complex
absorbing potential and complex scaling, resonant states can be
normalized. Using bound state coupled-cluster methods to the complex
Hamiltonian, resonance energies can be obtained as real part of complex
electron affinity and resonance widths can be obtained as imaginary
part. Test results to prototype systems are presented.