The Research On Spectroscopic Properties Of The Ground State And Excited States Of AsO~+Radical And GeO Molecule

Molecular spectroscopy is an important tool to investigate the molecular structure and properties. Bythe understanding of the molecular spectroscopy, we can obtain the molecular vibrational energy levels,rotational energy levels, et al. And the potential energy function is a useful method to study on themolecular spectroscopy. As for the potential energy function, it can completely describe the energy and thegeometrical structure and spectroscopic properties of the molecules with Born-Oppenheimer approximation.The PEF can solve the equation of the nuclear motion, which is the foundation to investigate atomic andmolecular collision and reaction, and plays an important role in the atom-cluster growth, dissociation andanalyses. So, it is one of the important research directions in atomic and molecular physics.In the present work, the molecular potential energy curves and spectroscopic parameters of the AsO+radical and GeO molecule are calculated basing on the relevant knowledge of the atomic and molecularreaction statics, quantum chemistry calculation and molecular potential energy function.Firstly, the high level quantum chemistry ab inito multi-reference configuration interaction methodwith large V5Z basis set is used to calculate the spectroscopic properties of the15Λ-S electronic states(X1Σ+, A1Π,1,1Σ-,3Σ+,3Π,3,3Σ-,5Σ+,5Π,5,1Π(II),5Σ+(II),1Π(III) and1Π(IV)) of AsO+radicalcorrelated to the dissociation limit As+(3P1g)+O(3Pg) and As+(1Dg)+O(Dg). In order to get better potentialcurves and more accurate spectroscopic properties, the Davidson modification is taken into account. Withthe PECs determined here, vibrational levels G(υ) and inertial rotation constants Bυare computed for all thebound electronic states when the rotational quantum number J equals zero (J=0). Except for the states X1Σ+,A1Π, it is the first time to use multi-reference configuration calculation on the13Λ-S electronic states ofAsO+radical. The potential energy curves of all the Λ-S electronic states are depicted according to theavoided crossing rule of the same symmetry. Spin-orbit coupling effect (SOC) is introduced to the statesX1Σ+, A1Π,3Π to consider its effects on the spectroscopic properties. Transition dipole moments (TDMs)from A1Π1,3Π1states to the ground state X1Σ+0+are predicted as well.Moreover，the full valence complete active space self-consistent field (CASSCF) method followed by the internally contracted multi-reference configuration interaction method (MRCI) is used to calculate theeight lowest Λ-S electronic states (X1Σ+, a3Σ+, d3, b3Π, e3Σ-, C1Σ-, D1, A1Π) of GeO molecule at thetheoretical level of aug-cc-pV5Z basis set, where Davidson modification is taken into account (MRCI+Q).Based on the above method, the bond length is circulated with the step of0.05to scan a series of thesingle-point energies. Because the curve shapes of the states C1Σ-, D1, e3Σ-are very similar and theexcited energy of the states b3Π and e3Σ-are rather closed, so the step of0.01is are used to scan from1.5to2.2, meanwhile the corresponding potential curves and spectroscopic constants of each state arecalculated as well, meanwhile, the excited energy order from low to high is also obtained. The spin-orbitcoupling (SOC) effect is introduced to the eight lowest Λ-S states and they split into15electronic states,then the spectroscopic constants of all the electronic states are obtained. Because the potential energycurves of all states are depicted according to the avoided crossing rule of the same symmetry, so, once thespin-orbit coupling effect is introduced into the computation, there are rather obvious effects on thespectroscopic constants, which prove the SOC effect is very important on the spectroscopic constants of theGeO molecule. Finally, the transition dipole moments (TDMs) are predicted as well.