MRSDCI study of the two lower‐lying doublet electronic states of the BeB, MgB, and CaB molecules

Abstract

Potential energy curves, dipole and transition moment functions, spectroscopy constants, radiative transition probabilities, and lifetimes for the two lower-lying doublet states (X 2 ⌸ and A 2 ⌺ ϩ ) of the BeB, MgB, and CaB molecules are reported with multireference singles and doubles configuration interaction methodology. Radiative lifetimes for Ј ϭ 0 are predicted to be 158 s, 281 s, and 87 s for BeB, MgB, and CaB, respectively. The strongest transitions from Ј ϭ 0 should occur to vibrational levels Љ ϭ 0 and 1 for BeB, to Љ ϭ 2 and 3, for MgB and to Љ ϭ 3 and 4 for CaB.

Ab initio calculations on potential energy curves and radiative lifetimes for the band systems A2Π–X2Σ+ of magnesium monohalides MgX (X=F, Cl, Br, I)

“…1 that the equilibrium distances of the X 2 R + and A 2 P states increase as the halogen atom varying from F to I, similarly to the trend reported previously in the equilibrium distances for the first two electronic states of the alkaline-earth monoborides BeB, MgB and CaB [18], alkaline-earth monocarbides BeC, MgC and CaC [19], and alkaline-earth monofluorides BeF, MgF and CaF [17]. The depths of potential well for both states of all molecules become more and more shallow, especially for the first excited state.…”

“…Recently, there are similar studies for the diatomic molecules formed by the alkaline-earth atoms (Be, Mg and Ca) with the second period atoms (F, B, C, and N) [17][18][19][20][21][22]. To provide detail results for future spectral analysis of these molecules, the present study aims to provide a unique comparative study of the spectroscopic properties with the theoretical approach for these magnesium monohalides.…”

Radiative transition probabilities and lifetimes for the band systems A²pi - X²sigma+ of the isovalent molecules BeF, MgF and CaF

“…At large distances the confi gurations change to properly describe a covalent structure at the dissociation limit M ( 1 S g ) + F ( 2 P u ). The equilibrium distances for the states X 2 Σ + and A 2 Π increase as the size of the metallic atom increases, similarly to the trend in the equilibrium distances for the fi rst two electronic states of the alkaline-earth monoborides BeB, MgB and CaB [17], and alkaline-earth monocarbides BeC, MgC and CaC [19]. For both states of all molecules, our R e results are slightly shorter than previous theoretical studies, thus improving the agreement with experiment.…”

“…However, for the CaF molecule, the radiative lifetime for ν = 0 of the A 2 Π → X 2 Σ + transitions was determined equal to 21.9 ± 4.0 ns directly from the rate of fluorescence decay using a pulsed dye laser as an excitation source [16]. Recently, we have also concluded similar studies for the diatomic molecules formed by the alkaline-earth atoms (Be, Mg and Ca) with the second period atoms (B, C and N) [17][18][19].…”

Laser spectroscopy of iridium monoboride

“…In the past few years, some efforts have been made to determine the spectroscopic properties of diatomic metal borides in gas-phase experimentally 4,5 and also to understand their bonding characteristics theoretically. [6][7][8][9][10] Iridium is also an important metal catalyst in the formation of carbon-hydrogen and carbon-oxygen bonds. 11,12 Iridium compounds' catalytic properties in chemical reactions are well known, but their spectroscopic properties are not ready available.…”