Exciton Theory of Excited States

3 Excited States and Correlation Effects in Polymers Intermediate Exciton Theory of Excited States.—It is well known that the HF picture does not permit a reasonable calculation of excited states and optical 

The many-particle wavefunction of Takeuti s method is constructed in the form 

Theory of Excitons, Solid State Phys. Suppl., 1963, 5, 1. 

The Green s function for the electron-hole pair is defined here by 

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