The electronic structure of transition metal dihelide dications

Abstract

Multi-reference configuration interaction (MRCI) calculations have been employed to characterize the low-lying states of first-row transition metal dihelide dications, He(2)TM(2+) (TM = Sc-Cu). The most important state-ordering principles were determined to be the occupation of the 4s orbital and orientation of the occupied 3d orbital. The ground states of all species are predicted to be of D(infinityh) symmetry arising from a 3d(n+1) electronic configuration. For excited states with singly occupied 4s or doubly occupied 3d(sigma) orbitals, bending to C(2v) symmetry typically lowers the energy and shortens the He-TM bond length. Coupled cluster singles and doubles with a perturbative treatment of triple excitations (CCSD(T)) results for ground state spectroscopic properties are in agreement with the MRCI predicted trends.

Gas-Phase Ion Chemistry of the Noble Gases: Recent Advances and Future Perspectives

“…99 Other helide and dihelide dications have also recently been predicted by theoretical calculations. [100][101][102] It is of interest that largesize M 2+ (He) n with n up to tens have recently been observed from the ionization of helium nanodroplets doped with Mg, Ag and Pb. 43,44 For Ag 2+ (He) n and Mg 2+ (He) n , the observed magic numbers were 4 and 6 and 4 and 8, respectively, 44 while the closure of a first solvation shell at n = 12 was inferred for Pb 2+ (He) n .…”

An ab initio study of the CrHe diatomic molecule: the effect of van der Waals distortion on a highly magnetic multi-electron system

“…Charged chromium-helium systems have been extensively analyzed in the past. [24][25][26][27] The inelastic collision rates and elastic cross sections for Cr and He were determined in experiments using He buffer gas cooling for loading a magnetic trap with chromium. 28 The ground state of the chromium dimer was investigated by several authors, using a wide range of theoretical methods.…”

Chemical Aristocracy: He3 Dication and Analogous Noble-Gas-Exclusive Covalent Compounds

“…The design of these systems usually involves replacing a hydrogen atom with Ng + or, alternatively, substituting a hydrogen ion with Ng 2+ within the molecular structure. The inherent challenges of conducting experimental studies in helium molecular ion chemistry, coupled with the computational tractability of these small-sized compounds, highlight the paramount significance of theoretical investigations in furthering our comprehension and predictive potential within this domain …”

“…The inherent challenges of conducting experimental studies in helium molecular ion chemistry, coupled with the computational tractability of these small-sized compounds, highlight the paramount significance of theoretical investigations in furthering our comprehension and predictive potential within this domain. 19 The resistance of noble gases to form chemical bonds, especially when electrically neutral, is not surprising. These elements possess exceptionally high excitation energies and exhibit the highest ionization potentials (IPs) within the periodic table.…”

“…The inherent challenges of conducting experimental studies in helium molecular ion chemistry, coupled with the computational tractability of these small-sized compounds, highlight the paramount significance of theoretical investigations in furthering our comprehension and predictive potential within this domain. 19 …”