Ab initio configuration interaction study of the electronic and geometric structure of small, mixed neutral and cationic MgNak and MgLik (k=2–8) clusters

An Intruder-Free Fock Space Coupled-Cluster Study of the Potential Energy Curves of LiMg+ within the (2,0) Sector

The potential energy curves (PECs) and spectroscopic constants of the ground and excited states of a LiMg+ molecular cation were investigated. We obtained accurate results for the fifteen lowest-lying states of the LiMg+ cation using the Intermediate Hamiltonian Fock Space Multireference Coupled Cluster (IH-FS-CC) method applied to the (2,0) sector. Relativistic corrections were accounted for using the third-order Douglas-Kroll method. In each instance, smooth PECs were successfully computed across the entire range of interatomic distances from equilibrium to the dissociation limit. The results are in good accordance with previous studies of this molecular cation. Notably, this study marks the first application of IH-FS-CC in investigating a mixed alkali and alkaline earth molecular cation, proving its usability in determining accurate PECs of such diatomics and their spectroscopic constants.

An ab initio investigation on the low-lying electronic states of NaMg

Theoretical investigations for NaMg have been performed on the icMRCI + Q level employing basis set of quintuple-ζ quality with corrections of core-valence correlation and scalar relativistic effect. The geometrical parameters, potential energy curves, vibrational energy levels, spectroscopic constants for the eight Λ-S states, with respect to the lowest four dissociation limits, are investigated. Through the spin-orbit coupling effect, these states split into fourteen Ω states. The permanent dipole moments, transition dipole moments, Einstein emission coefficients, radiative lifetimes and Franck-Condon factors for all Ω states are studied. The feasibility of performing laser cooling of NaMg has also been discussed. Our predictive results are anticipated to serve as guidelines for further researches on NaMg.

SUPERALKALI MOLECULES CONTAINING HALOGENOIDS

The structure and properties of hypermetalated Li 2X and Na 2X and their corresponding Li 2X+ and Na 2X+ cations utilizing halogenoids X (SCN, OCN, and CN) were investigated using ab initio methods at the CCSD(T)/6-311+G(3df)//MP2/6-311+G(d) level of theory. The vertical ionization potentials of Li 2X and Na 2X radicals were calculated at the outer valence Green function level (OVGF) with the 6-311+G(3df) basis sets. It was found that all Na 2X molecules studied possess the vertical ionization potentials (VIP) that are smaller than the IP of the Na atom (5.14 eV) and thus may be termed superalkali molecules, whereas the Li 2X radicals exhibit slightly larger IPs. The smallest VIP of 4.728 eV was calculated for the Na 2 CN system. The IP dependence on the structure and the singly occupied molecular orbital (SOMO) character is also discussed.

Ab initio properties of MgAlk (Alk = Li, Na, K, Rb, Cs)

High level ab initio calculations are performed on the ground electronic state of diatomic molecules MgAlk (Alk = Li, Na, K, Rb, Cs). Potential energy curves and dipole moment functions are determined making use of the single-reference unrestricted and restricted coupled-cluster methods with large basis sets. Basic spectroscopic properties of the ground electronic states are derived from ro-vibrational bound state calculations.

The Na2X Superalkali Species (X=SH, SCH3, OCH3,CN, N3) as Building Blocks in the Na2XY Salts (Y=MgCl3, Cl, NO2). An Ab Initio Study of the Electric Propertiesof the Na2XY Salts

Vertical and adiabatic ionization potentials of Na2X (X = SH, SCH3, OCH3, CN, and N3) superalkali molecules have been studied using the ab initio methods. The smallest vertical ionization potential was calculated for the Na2OCH3 system (4.365 eV). The Na2X molecules were found to be capable of forming stable [Na2X]+[Y]– salts with the species exhibiting various electron affinities (Y = MgCl3, Cl, NO2). The dipole moments, polarizabilities, and first-order hyperpolarizabilities of the Na2XY ionic salts were calculated and discussed. It was found that the Na2XNO2 molecules possess extraordinary large values of anisotropy of polarizabilities (in the 15.5–28.2 × 10–24 esu range) and the first-order hyperpolarizbilities (spanning the 597.8–1295.7 × 10–30 esu range).

Geometric, electronic, and bonding properties of AuNM (N=1–7, M=Ni, Pd, Pt) clusters

Employing first-principles methods, based on density functional theory, we report the ground state geometric and electronic structures of gold clusters doped with platinum group atoms, Au(N)M (N = 1-7, M = Ni, Pd, Pt). The stability and electronic properties of Ni-doped gold clusters are similar to that of pure gold clusters with an enhancement of bond strength. Due to the strong d-d or s-d interplay between impurities and gold atoms originating in the relativistic effects and unique properties of dopant delocalized s-electrons in Pd- and Pt-doped gold clusters, the dopant atoms markedly change the geometric and electronic properties of gold clusters, and stronger bond energies are found in Pt-doped clusters. The Mulliken populations analysis of impurities and detailed decompositions of bond energies as well as a variety of density of states of the most stable dopant gold clusters are given to understand the different effects of individual dopant atom on bonding and electronic properties of dopant gold clusters. From the electronic properties of dopant gold clusters, the different chemical reactivity toward O(2), CO, or NO molecule is predicted in transition metal-doped gold clusters compared to pure gold clusters.

Cluster ions ejected from an Li-Mg alloy liquid metal ion source: Observation of MG 2 (2+) and MG 3 (2+)

Ions ejected from a liquid metal ion source of an Li-Mg (10 atom %) alloy have been investigated by using a magnetic mass analyzer. In addition to singly charged homonuclear Li n (+) (n ≤ 9) and Mg n (+) (n ≤ 4) and heteronuclear MgmLi n (+) (m, n ≤ 2) clusters, doubly charged diatomic and triatomic Mg clusters are observed. Discussion is focused on the observability and the formation mechanism of the doubly charged small Mg clusters. A postionization process is suggested for the formation of the doubly charged clusters.