The theoretical possibility of the existence of a metastable CO{sub 4} molecule

The possibility of the existence of a CO{sub 4} molecule is considered theoretically. Based on the selection rules for chemical reactions and the results of the appropriate quantum mechanical calculations, it is shown that the ground electronic state X{sup 1}A{sub 1} of this molecule must be metastable, with D{sub 2d} symmetry of its nuclear configuration. The frequencies of normal vibrations and the equilibrium structural parameters of the molecule are determined for this state. The adiabatic decomposition of CO{sub 4}(X{sup 1}A{sub 1}) must be accompanied by formation of the singlet oxygen O{sub 2}(a{sup 1} {triangle}{sub g}) and by heat release. This decomposition is forbidden by the orbital symmetry rules, so that it must be impeded by a high potential barrier. Theore tically, the CO{sub 4}(X{sup 1}A{sub 1}) molecule can be obtained in the exothermic reaction CO{sup 3}(X{sup 1}A{sub 1}). 29 refs., 1 fig., 1 tab.