conical intersections, theoretical chemistry, non-adiabatic chemistry, non Born-Oppenheimer effects


Chemistry | Mathematics


Richard Lord


Conical intersections (CIs) are points of degeneracy between two or more potential energy surfaces. Due to the intersection point, it is much easier for molecules to transition their electronic, vibrational, and rotational energies between surfaces. Therefore, CIs are critical to the study of excited states, particularly in the context of photochemistry. However, they are difficult to study because they interfere with traditional thermodynamics and deviate from the Born-Oppenheimer approximation. The purpose of this review is to explain why that is the case by exploring the foundation for the mathematics and physics behind CIs. Also included is an application of how CIs effect real chemical systems.