Theoretical Study on Radiationless Decay in Butadiene Isomerization Case using First-principles Calculation

Abstract

This study is to learn the radiation-less decay in butadiene isomerization from skew- to trans- conformation based on energy level diagram. We construct energy level diagram to determine the energy difference of butadiene in transition geometry between ground state and excited state with the basis of first-principles calculations. We use density functional theory for ground state butadiene while configuration interaction and complete active space for the excited state. The result is that the energy difference is 0.005 eV. It implies that there is degeneration occurred at the transition state of butadiene between its ground state and excited state. We conclude that conical intersection may occurs in the butadiene isomerization reaction.