Barysz Maria
Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland.
J Phys Chem A. 2024 Sep 12;128(36):7601-7608. doi: 10.1021/acs.jpca.4c04032. Epub 2024 Aug 31.
Our study provides a comprehensive theoretical examination of the energy levels associated with the neutral tantalum atom and its ions in various charge states (Ta, Ta, and Ta), employing the multiconfiguration Dirac-Hartree-Fock (MCDHF) method, and relativistic infinite order two-component (IOTC) method with multiconfiguration complete active space self-consistent field (CASSCF) followed by the second-order single-state multireference perturbation (CASPT2) methods. The effect of spin-orbit (SO) coupling is introduced via the restricted active space state interaction (RASSI) method, utilizing atomic mean field SO integrals (AMFI). Through IOTC CASSCF/CASPT2 RASSI calculations, we determined the electron affinity (EA) of the tantalum atom to be 0.321 eV, which stands among the most accurate theoretical values achieved to date. This result closely aligns with the experimental measurement of 0.329 eV. Our investigation highlights potential discrepancies between the predicted symmetry of the excited states of the tantalum anion and experimental observations. Additionally, we calculated the bonding energies for transitions from Ta to Ta and identified four potential bound or quasi-bound states in the tantalum anion.
我们的研究采用多组态狄拉克 - 哈特里 - 福克（MCDHF）方法，以及相对论无限阶二分量（IOTC）方法与多组态完全活性空间自洽场（CASSCF）并结合二阶单态多参考微扰（CASPT2）方法，对与中性钽原子及其不同电荷态（Ta、Ta和Ta）离子相关的能级进行了全面的理论研究。通过受限活性空间态相互作用（RASSI）方法，利用原子平均场自旋 - 轨道（SO）积分（AMFI）引入自旋 - 轨道（SO）耦合效应。通过IOTC CASSCF/CASPT2 RASSI计算，我们确定钽原子的电子亲和能（EA）为0.321电子伏特，这是迄今为止所获得的最精确理论值之一。该结果与0.329电子伏特的实验测量值非常接近。我们的研究突出了钽阴离子激发态预测对称性与实验观测之间的潜在差异。此外，我们计算了从Ta到Ta跃迁的结合能，并在钽阴离子中确定了四个潜在的束缚态或准束缚态。
