Preferred Label : avoided crossing;
Detailed label : avoided crossing of potential-energy surfaces;
IUPAC definition : Frequently, two Born–Oppenheimer electronic states (A, B) change their energy order
as molecular geometry ( i x /i ) is changed continuously along a path. In the process
their energies may become equal at some points (the surfaces are said to cross, dotted
lines in the figure), or only come relatively close (the crossing of the surfaces
is said to be avoided). If the electronic states are of the same symmetry, the surface
crossing is always avoided in diatomics and usually avoided in polyatomics. Synonymous
with intended crossing.;
Origin ID : A00544;
See also
Frequently, two Born–Oppenheimer electronic states (A, B) change their energy order
as molecular geometry ( i x /i ) is changed continuously along a path. In the process
their energies may become equal at some points (the surfaces are said to cross, dotted
lines in the figure), or only come relatively close (the crossing of the surfaces
is said to be avoided). If the electronic states are of the same symmetry, the surface
crossing is always avoided in diatomics and usually avoided in polyatomics. Synonymous
with intended crossing.
