在线词典

In quantum physics and quantum chemistry, an avoided crossing (sometimes called intended crossingfor a less mathematical explanation see IUPAC Goldbook article or non-crossing, anticrossing) is defined as the case when the eigenvalues of a Hermitian matrix depending on N continuous real parameters cannot cross (that is, two or more eigenvalues cannot become equal in value) except at a manifold of N-2 dimensions. In the case of a diatomic molecule (one parameter, which describes the bond length), this means that the eigenvalues do not cross.