Characterization of Homonuclear Diatomic Ions by Semiempirical Morse Potential Energy Curves. 2. The Rare Gas Positive Ions

Abstract

Morse potential energy curves for the lowest six states of the rare gas positive ion dimers have been calculated on the basis of experimental data. For the ground states, there are sufficient measured data to define the curves completely. For the excited states of all the positive ion dimers except neon, there are sufficient measured data to define the curves. To obtain these curves, new assignments of vibrational progressions in high-resolution photoelectron spectra previously published are made and the vertical ionization potentials obtained. The vertical ionization potentials are used to determine the internuclear distances. The ground state ionic and neutral radii for Ne to Xe are 63, 93, 105, and 123 pm and 112, 152, 168, and 194 pm, respectively. “Virtual” covalent radii for Ne to Xe are 69, 98, 111, and 126 pm. The curves are consistent with the van der Waals radii of Ne to Xe, which are 154, 188, 200, and 218 pm. From the correlation between the Morse parameters of the isoelectronic ions and the new data for the rare gas positive ions, improved Morse potential energy curves for both the halogen negative ion dimers and the rare gas positive ion dimers are obtained.

Pulsed-Field Ionization Zero-Kinetic-Energy Photoelectron Spectra of Ar2

“…As mentioned above, these peaks are assigned to the C 2 ⌸ 3/ 2u state by Hall et al (18). However, we assigned these peaks to the B 2 ⌸ 1/ 2g state on the basis of theories proposed in other papers (1)(2)(3)(4) …”

“…The first four states dissociate to the Ar ( 1 S 0 ) ϩ Ar ϩ ( 2 P 3/2 ) limit, and the remaining two states dissociate to the Ar ( 1 S 0 ) ϩ Ar ϩ ( 2 P 1/2 ) limit. The ionic states of Ar 2 were calculated by Wadt (1), Michels et al (2), Gadea and Paidarová (3), and Chen et al (4). Experimental investigations on the ionic states of Ar 2 were also performed by Ng et al (5), Moseley et al (6), Dehmer and Dehmer (7), Dehmer and Pratt (8), Norwood et al (9), Pradeep et al (10), Weitzel et al (11), and Signorell et al (12).…”

What can we learn from two‐center three‐electron bonding with the topological analysis of ELF?

“…From a theoretical point of view, the most frequently studied species are the rare gas dimer cations [46,47], dihalogen anions [48][49][50], and disulfide ions [51][52][53][54][55], which have long been experimentally identified. In two landmark papers, Clark [3] and Gill and Radom [39] investigated all the model systems of the type H m X І YH + n , attempting to rationalize the existence of 2c-3e bonds.…”

Chemical Processes in the Space Environment

“…45 " 51 The ultraviolet absorption bands of Ar^ involve the parallel 2 X*<-2 X* transition which has an absorption maximum at 317 nm. 52 The dissociation energy of Ar^ is 1.38±0.05 eV, 53 and the excited 2 X* correlates with the formation of Ar + in the excited 2 P m spin-orbit component which in turns lies 0.18 eV above the ground state. At 300 nm (4.13 eV), the dissociation occurs almost exclusively on the purely repulsive 2 X^" surface, and the photon energy is 2.57 eV above the dissociation threshold.…”