Electronic states of diatomic molecules

Fumi, F. G., and Parr, R. G., /. Chew. Phys. 21, 1864, Electronic states of diatomic molecules The oxygen molecule. ... 

Most of the infrared laser lines originating from transitions between vibrational-rotational levels in different electronic states of diatomic molecules, e. g. N2, Oj, H, D2, CO, CN, etc., have been meanwhile correctly indentified Some lines and term systems have been found which had never been observed before 354a)... 

Auzinsh, M.P., Tamanis, M.Ya. and Ferber, R.S. (1986). Zeeman quantum beats during the transient process after optical depopulation of the ground electronic state of diatomic molecules, Sov. Phys.—JETP, 63, 688-693. 

There are three different schemes for building up the electronic states of diatomic molecules (a) from separated atoms, (b) from the united atom, and (c) from the molecular orbitals of the diatomic molecule itself. It is the correlation between the electronic states of the diatomic molecule as built up from the separated atoms and as determined from the molecular orbitals of the diatomic which is most valuable for any general consideration of reactions and excited states. The correlation of molecular states obtained by these two methods is not limited solely to diatomic molecules but also forms a valid approach for polyatomic molecular systems. The correlation of separated atoms with the hypothetical united atom has value for diatomics and has been applied to simple polyatomic molecules, especially those with a heavy atom or two and a number of hydrogen atoms. However, it is conceptually less appealing even for simple polyatomic molecules and completely inapplicable for complex polyatomic molecules. 

A similar idea to that involved in EPCE-F26" was used for the estimates of correlation energy in different electronic states of diatomic molecules. The essence of that approach is the conversion of the MO representation of the electronic structure of a particular electronic state to the atomic representation by means of the population analysis and the assumption that the predominant correlation effects are due to electron pairs in the same orbital. In this way, the correlation energy is again given by the products of AO populations and AO correlation contributions (available in the literature). Although the approach is rough, it may be useful for spectroscopic purposes. Table 4.2 presents an example of the treatment of this type. 

I 2.1 Rotational Energy Levels of Diatomic Molecules, K I 2.2 Vibrational Energy Levels of Diatomic Molecules, 10 I 2.3 Electronic States of Diatomic Molecules, 11 1 2.4 Coupling of Rotation and Electronic Motion in Diatomic Molecules Hund s Coupling Cases, 12 I-,3 Quantum States of Polyatomic Molecules, M... 

Kaslin, V.M. 1983a. Tables of Force Constants ke and Vibrations Constants coe of Ground Electronic States of Diatomic Molecules, Composed ofAtoms with Composition of s and p Shells (Atom from the Chemical Groups of Lithium, Beryllium, Boron and Carbon). Preprint 302. Moscow Optics Laboratory, Optics and Spectroscopy Department, Physical Institute. 

We have concentrated mostly on the ground electronic states of diatomic molecules. In this section we consider some of the excited states of H2. Figure 13.19 gives the potential-energy curves for some of the H2 electronic energy levels. 

For electronic states of diatomic molecules in which the electrons have a resultant angular momentum around the internuclear line (see section 25) J may also stay unaltered. Since the vibration-rotation spectra are all obtained in absorption and hence refer to the ground state, and since NO is the only diatomic molecule in the ground state of which the electrons have an angular momentum around the internuclear line, we disregard this special case in the subsequent investigation. 

In [194] the authors presented the comparison of three variational approaches for solving the radial Schrodinger equation. In the comparison special attention was spent to accurate computation of the vibrational energy levels lying close to the dissociation limit in bound electronic states of diatomic molecules. The above mentioned methodologies are studied on the ground state of the hydrogen molecule. 

Wigner and Witmer s [5] characterization of the electronic states of diatomic molecules marked the triumphant entry of group theory into the field of molecular structure. It was focused primarily on considerations of angular momentum, which we have managed to sidestep almost completely thus far in the book by artificially reducing spherical or cylindrical symmetry to Thus, the cr... 

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