A relativistic time-dependent density functional study of the excited states of the mercury dimer

Abstract

In previous works on Zn2 and Cd2 dimers we found that the long-range corrected CAMB3LYP gives better results than other density functional approximations for the excited states, especially in the asymptotic region. In this paper, we use it to present a time-dependent density functional (TDDFT) study for the ground-state as well as the excited states corresponding to the (6s(2) + 6s6p), (6s(2) + 6s7s), and (6s(2) + 6s7p) atomic asymptotes for the mercury dimer Hg2. We analyze its spectrum obtained from all-electron calculations performed with the relativistic Dirac-Coulomb and relativistic spinfree Hamiltonian as implemented in DIRAC-PACKAGE. A comparison with the literature is given as far as available. Our result is excellent for the most of the lower excited states and very encouraging for the higher excited states, it shows generally good agreements with experimental results and outperforms other theoretical results. This enables us to give a detailed analysis of the spectrum of the Hg2 including a comparative analysis with the lighter dimers of the group 12, Cd2, and Zn2, especially for the relativistic effects, the spin-orbit interaction, and the performance of CAMB3LYP and is enlightened for similar systems. The result shows, as expected, that spinfree Hamiltonian is less efficient than Dirac-Coulomb Hamiltonian for systems containing heavy elements such as Hg2.

Comparing a mercury optical lattice clock with microwave and optical frequency standards

“…[37] using the measured fraction of detected atoms and mercury properties from refs. [38,39]. We obtain a shift of −2 × 10 −17 .…”

“…Another source of systematic uncertainty related to atom-atom interactions are background collisions. We evaluate this shift by applying the theory of [36] using the measured fraction of detected atoms and mercury properties from [37,38]. We obtain a shift of -´-2 10 17 .…”

A High-Precision Calculation of Bond Length and Spectroscopic Constants of Hg 2 Based on the Coupled-Cluster Theory with Spin—Orbit Coupling

“…In fact, Kullie has already used a relativistic four-component Dirac-Coulomb Hamiltonian with the spin-orbit coupling in the framework of the timedependent density functional theory and linear response approximation to calculate the electronic states of Hg 2 . [11] However, it is widely known that the results of spectroscopic constants are very dependent on the choice of functional. The more general and highprecision ab initio calculations such as the coupledcluster calculation with spin-orbit coupling based on two-component ECPs are desired and will be helpful to understand the spectral character of Hg 2 .…”