NUCLEAR-QUADRUPOLE INTERACTIONS IN ATOMS AND MOLECULES

The basic concepts of the nuclear quadrupole coupling in atoms and mol ecules are presented. Unlike the common sources of experimental inform ation on nuclear quadrupole coupling in molecules, namely microwave, N MR and NQR spectroscopies, laser-induced fluorescence and saturated ab sorption spectroscopies are capable of providing a wealth of data on t he hyperfine quadrupole splitting in excited electronic and vibrationa l states. Practical procedures for calculating the nuclear quadrupole coupling in rovibronic states of diatomic molecules are shortly discus sed.