An ab initio study of the ground and low-lying excited states of KBe with the effect of inner-shell electrons

Abstract

The potential energy curves (PECs) of 1(2)Σ(+), 2(2)Σ(+), 1(2)Π, and 2(2)Π states of KBe are calculated using multireference configuration interaction method and large all-electron basis sets. Four sets of frozen core orbitals (FCOs) are considered to examine the effect of inner-shell correlation electrons on the molecular properties. The ro-vibrational energy levels are obtained by solving the Schrödinger equation of nuclear motion based on the ab initio PECs. The spectroscopic parameters are determined from the ro-vibrational levels with Dunham expansion. The PECs are fitted into analytical potential energy functions using the Morse long-range potential function. The dipole moment functions of the states for KBe calculated with different FCOs are presented. The transition dipole moments for KBe between 1(2)Σ(+) and 2(2)Σ(+) states, 1(2)Π and 1(2)Σ(+) states, and 2(2)Π and 1(2)Σ(+) states are also obtained.

Ab Initio Study on the Ground and Low-Lying States of BAlk (Alk = Li, Na, K) Molecules

“…Up to date, we are unaware of any experimental studies of vibrational and rotational levels and electronic spectroscopy of these molecules. Considering that the accuracy of the present computational level has been confirmed in the cases of KLi and KBe molecules, 10,11 we believe that the present calculated results for BAlk molecules can provide helpful references for further investigations.…”

“…Ro-vibrational Energy Levels and Spectroscopic Parameters. Using LEVEL8.0 25 to solve the Schrodinger equation of the nuclear motion with the obtained PECs, we have obtained the vibrational energy levels for J = 0 for 1 Π, 3 Π, 1 Σ + , and 3 Σ + states of 11 BAlk (Alk = 7 Li, 23 Na, 39 K) molecules. For the sake of brevity, we only present the first 20 levels in Table 1 (complete data are in the Supporting Information).…”

“…■ ASSOCIATED CONTENT * S Supporting Information Tables S1−S3: total vibrational levels (J = 0) of the for 3 Π, 1 Π, 1 Σ + , and 3 Σ + states of 11 BAlk (Alk = 7 Li, 23 Na, 39 K), respectively. Tables S4 and S5: parameters of MLR potential energy functions for 3 Π, 1 Π, 1 Σ + , and 3 Σ + states of BNa and BK, respectively.…”

“…The ro-vibrational or scattering wave functions, which are more concrete and important to decide the type of laser for PA transition can be obtained on the basis of the reliable PECs and TDMs. Excellent results have been achieved for low-lying excited states of KLi and KBe molecules with large basis sets and inner-shell electron correlation. Therefore, we decided to extend the high level ab initio study to the ground state and low-lying states of BAlk (Alk = Li, Na, K) molecules.…”

“…Spectroscopic Parameters for 3 Π, 1 Π, and 1 Σ + States of11 B 39 K a The number in parentheses that follows a quantity is the exponent of 10 that multiplies the quantity. Values of the parameters are in cm −1 unless otherwise noted.…”