The elusive CH²⁺ion

Abstract

Experiments with an electron cyclotron resonance ion source have been employed in a hunt for the elusive CH2+ ion. The authors' experiments do not find evidence for the existence of stable CH2+ ions. Different levels of ab initio molecular orbital theory have been employed to obtain potential energy curves for CH2+. Although SCF calculations show a small minimum in the potential, post-Hartree-Fock computations indicate CH2+ states to be repulsive.

Formation of long-lived CDn2+and CHn2+dications

“…Since the first observation the identity of the long-lived state of CH 2+ has been debated. Furthermore, some have questioned if such long-lived states do exist (see, for example, Koch et al 1987, Wetzel et al 1993. As this controversial issue is not the topic of this study we will refer those interested to a few recent publications where it is discussed in detail by Gu et al (1998) and Ben-Itzhak et al (1999a).…”

“…The improved understanding of the structure and properties of the CH 2+ n dications was strongly affected by theoretical studies (see, for example, Pople et al 1982, Siegbahn 1982, Heil et al 1983, Wetmore et al 1984, Koch et al 1987, Hamdan et al 1988, Wetzel et al 1993, Gu et al 1998. It has been suggested, for example, that CH 2+ 4 has a planar geometry, and § Author to whom corrspondence should be addressed.…”