Structural, Spectroscopic, and Dynamic Properties of Li2+(X2∑g+) in Interaction with Krypton Atom

Abstract

We report a computational study of the potential energy surface (PES) and vibrational bound states for the ground electronic state of Li2+Kr. The PES was calculated in Jacobi coordinates at the Restricted Coupled Cluster method RCCSD(T) level of calculation and using aug-cc-pVnZ (n = 4 and 5) basis sets. Afterward, this PES is extrapolated to the complete basis set (CBS) limit for correction. The obtained interaction energies were, then, interpolated numerically using the reproducing kernel Hilbert space polynomial (RKHS) approach to produce analytic expressions for the 2D-PES. The analytical PES is used to solve the nuclear Schrodinger equation to determine the bound states’ eigenvalues of Li2+Kr for a J = 0 total angular momentum configuration and to understand the effects of orientational anisotropy of the forces and the interplay between the repulsive and attractive interaction within the potential surface. In addition, the radial and angular distributions of some selected bound state levels, which lie below, around, and above the T-shaped 90° barrier well, are calculated and discussed. We note that the radial distributions clearly acquire a more complicated nodal structure and correspond to bending and stretching vibrational motions “mode” of the Kr atom along the radial coordinate, and the situation becomes very different at the highest bound states levels with energies higher than the T-shaped 90° barrier well. The shape of the distributions becomes even more complicated, with extended angular distributions and prominent differences between even and odd states.

Potential Energy Surface and Bound States of Ne–Li2+(X2Σg+) van der Waals Complex Based on Ab Initio Calculations

“…Distinct disparities between even and odd states become evident in the radial and angular probability distributions for levels of n = 27 and beyond. In the case of the highest bound states, as depicted in Figure , the shape of these distributions becomes even more complex, featuring extended angular distributions and pronounced distinctions between states with even and odd parity, specifically for states. ,, …”

“…These functions are expressed as follows q 1 n , m ( x , x ′ ) = n 2 x > − ( m + 1 ) B false( m + 1 , n false) 2 F 1 ( − n + 1 , m + 1 ; n + m ; x < x > ) q 2 ( y , y ′ ) = ∑ l false( 2 l + 1 false) 2 P l ( y ) P l ( y ′ ) where x > and x < are the larger and smaller values of x and x ′, respectively. Based on our recent work for similar interactions (Li 2 + Kr), it is assumed that the 2D-PES V ( R ,θ) of Ne–Li 2 + X 2 Σ g + can be described as a continuous function that possesses second-order derivatives, denoted by n = 2, with respect to both R and θ. Furthermore, to accurately incorporate the prevailing dispersion interaction between the Ne atom and the ionic dimer Li 2 + , a weighting factor w ( x ) = x – m with m = 3 is introduced.…”

“…In the case of the highest bound states, as depicted in Figure 11 , the shape of these distributions becomes even more complex, featuring extended angular distributions and pronounced distinctions between states with even and odd parity, specifically for states. 17 , 25 , 26 …”

“…From a theoretical perspective, recent contributions by researchers such as Saidi et al have delved into the structural, spectroscopic, and dynamic properties of Li 2 + ( X 2 Σ g + ) interacting with krypton atoms. Additionally, investigations by Alharzali et al, , Bodo et al, − and Marinetti et al have centered around the structure and dynamic characteristics of cationic dimers (Li 2 + , Na 2 + , and K 2 + ) interacting with helium atoms, employing approaches like RCCSDT and post-Hartree–Fock methods.…”