Theoretical Study on the Opacity of BH Molecule

BH molecule, which plays an important role in space, has been researched for a long time. The <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{X}^{1}\boldsymbol{\Sigma}^{+}, \mathbf{A}^{1}\boldsymbol{\Pi}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{a}^{3}\Pi$</tex> electronic states of BH molecule are calculated by the multireference configuration self-consisted filed (MRCI) + Q method with the scalar relativistic correction and core-valence correlation correction. In order to confirm the accuracy of the calculation results for potential energy curves (PECs), spectroscopic constants of the bound states, which in excellent agreement with measurements, are calculated. The transition dipole moment (TDM of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{X}^{1}\boldsymbol{\Sigma}^{+}-\mathbf{A}^{1}\boldsymbol{\Pi})$</tex> and the dipole moments (DMs) are also obtained by MRCI method. Based on the calculated results, the opacity of BH molecule at a pressure of 100 atms with temperatures of 500 K, 1000 K, 1500 K and 2500 K are provided. It is shown that the opacities for transitions in a long wavelength range are enlarged with the increase of temperature on account of the larger population on excited electronic states at the higher temperatures.