MRCI investigations on dissociation energy and molecular constants of BCl(X¹Σ⁺) radical

Abstract

ABSTRACT:The equilibrium internuclear separations and harmonic frequencies of the BCl(X 1 R þ ) radical have been studied using the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach in combination with a series of correlation-consistent basis sets in the valence range. To accurately determine the ground-state dissociation energy of the radical, the potential energy curve (PEC) is calculated at each basis set over the internuclear distance range from about 0.08 to 2.00 nm so as to affirm that the PEC is completely smooth and convergent. The PECs are all fitted to the Murrell-Sorbie function form, which are employed to reproduce the spectroscopic parameters, such as x e v e , a e , B e , and D 0 . The present D 0 , D e , R e , x e , x e v e , a e , and B e obtained at the MRCI/aug-cc-pV5Z level of theory with the , and 0.6860 cm À1 , respectively, which almost perfectly conform to the available measurements. The effects on the spectroscopic parameters by the relativistic corrections at different basis sets have been taken into considerations. With the potential determined at the MRCI/aug-cc-pV5Z level of theory, which considers the relativistic corrections, a total of 90 vibrational states is predicted when the rotational quantum number J equals zero (J ¼ 0) by numerically solving the radial Schrö dinger equation of nuclear motion. For each vibrational state, one vibrational level and corresponding classical turning points, one inertial rotation and six centrifugal distortion constants are determined when J ¼ 0, which are in excellent agreement with the available experimental data.

Structural parameters of the ground states of the quasi‐stable diatomic anions CO−, BF−, and BCl− as obtained by conventional Ab Initio methods

“…The overall comparison of the present results with experiment and those of Ref. at the MRCI+scalar relativity (DK2)/aug‐cc‐pV5Z level shows that scalar relativistic effects are unimportant, whereas small deviations from experiment are due to missing core (1s 2 / B 1s 2 2s 2 2p 6 / Cl ) correlation effects. It is of interest, however, to notice the following: (a) the electric dipole moment µ reported here for the first time and unknown experimentally is 1.34–1.35 D, obtained either as an expectation value < µ > or using the finite field approach, µ ff .…”

“…The first part of Table collects CC and MRCI(+Q)/A6ζ spectroscopic parameters of BCl( X 1 Σ + ) along with experimental and theoretical results from Ref. . The overall comparison of the present results with experiment and those of Ref.…”

“…The closed shell chloroborane (BCl; X 1 Σ + ) molecule is isovalent to BF and CO, and erroneously described as a radical in two recent publications . The first part of Table collects CC and MRCI(+Q)/A6ζ spectroscopic parameters of BCl( X 1 Σ + ) along with experimental and theoretical results from Ref.…”

Electronic states and spin-forbidden cooling transitions of AlH and AlF

“…18 This was a MRCI study using the AV5Z basis set of Dunning and co-workers on both atoms. 38,39 The same basis set was used in a recent calculation of the X 1 S + state 40 that concentrated on the vibrational levels of the radical. A (1 + 1) Resonance Enhanced Multiphoton Ionisation (REMPI) study by Zhu et al 41 reported spectroscopic constants for the spin-forbidden transition b 3 S À ' X 1 S + and C 1 S + ' X 1 S + .…”

Combining ab initio and machine learning method to improve the prediction of diatomic vibrational energies

“…Then Equation ( 2) can be solved by LEVEL [26] to obtain E ab inito ν . The corresponding experimental data are collected [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44], and used to construct offset data set. There are hundreds of records here, the first few rows are listed in Table 1.…”