Heteronuclear diatomics, electronic structure

In many cases the molecular orbitals for a heteronuclear diatomic molecule may be worked out in a straightforward manner as for hydrogen chloride. In others, however, certain difficulties arise and we shall take as an example the case of carbon monoxide, the structure of which has been the subject of much controversy. In carbon monoxide, as in the nitrogen molecule, there are fourteen valency electrons and Mullikan has formulated the structure of both molecules as... 

The molecular orbital description of period 2 diatomic molecules leads to bond orders in accord with the Lewis structures of these molecules. Further, the model predicts correctly that O2 should exhibit param pietism, which leads to attraction of a molecule into a magnetic field due to the influence of unpaired electrons. Molecules in which all the electrons are paired exhibit diamagnetism, which leads to weak repulsion from a magnetic field. The molecular orbitals of heteronuclear diatomic molecules are often closely rdated to those of homonuclear diatomic molecules. 

Heteronuclear diatomic ions with large vibrational and rotational frequencies are promising systems for high-precision laser spectroscopy and fundamental studies, such as tests of time independence of the electron-to-proton mass ratio. They can also serve as model systems for the implementation of schemes for internal state manipulation [79,80]. Molecular hydrides, such as ArH+ and ArD" ", are interesting examples, with the advantage of a relatively simple hyperfine structure of the rovibrational transitions [79,81]. These hydrides were formed by the ion-neutral reactions [49] (Figure 18.28a through c)... 

Franck-Condon factors. The most common angular momentum coupling cases are discussed, and rotational fine structure in electronic transitions (cf. Fig. 4.3) is rationalized for heteronuclear and homonuclear diatomics using Herzberg diagrams. 

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