SEARCH Articles Figures Tables Adiabatic representation Born-Huang expansion Born-Huang approximation Born-Huang approximation electronic states Born-Huang approximation equations Born-Huang approximation wave function Born-Huang expansion Electronic state adiabatic representation Born-Huang expansion Electronic states Born-Huang expansion Hilbert space Born-Oppenheimer-Huang equation Non-adiabatic coupling Born-Oppenheimer-Huang equation