Born-Oppenheimer 1927: separates nuclear + electronic motion via mass-ratio expansion (m_e/m_n)^(1/4); validates fixed-nuclei electronic structure calculation; breaks down at conical intersections.
Born-Oppenheimer 1927: separates nuclear + electronic motion via mass-ratio expansion (m_e/m_n)^(1/4); validates fixed-nuclei electronic structure calculation; breaks down at conical intersections.