OClO里德堡态激发能的准确预测及其阴离子低能激发态的从头算研究

采用全活化空间自洽场方法(CASSCF)研究了OClO阴离子7个低能电子态及其自由基的基态. 为了进一步考虑动态电子相关效应, 采用二级多组态微扰理论(CASPT2)获得更加可靠的能量值. 此外, 在ANO-L基组的基础上, 在OClO自由基的电荷中心增加了为研究里德堡态所建立的1s1p1d的波函数, 并应用多组态二级微扰理论(MS-CASPT2)方法获得了里德堡态的准确电子激发能.

Accurate Prediction of Excited Energy of Rydberg States of OCIO and Ab lnitio Investigation of Excited States of OCIO Anion with a Low Energy

By using the complete active space self-consistent field (CASSCF) method with large atomic natural orbital (ANO-L) basis set, seven electronic states of the OClO- anion were calculated. The optimized geometry of the ground state with ANO basis set agrees better with the experimental and previous theoretical values. Furthermore, the stable geometries of three singlet and three triplet excited states were obtained. Taking the further correlation effects into account, the second-order perturbation (CASPT2) calculations were carried out for the energetic calibration. Furthermore, the Rydberg states of the OClO radical were investigated by using multiconfigurational CASPT2 (MS-CASPT2) theory under the basis set of ANO-L functions augmented with an adapted 1s1p1d Rydberg functions that have specially been built for this study. Ten electronic excited states were found for the transition from 3b1 electron into the Rydberg orbitals. The 3b1→ns and 3b1→np series agreed excellent with the experimental values, and the assignment of 3b1→3d series supported the results of Marston. Meanwhile, two and four Rydberg states were computed for the transition of 1a2 and 5b2 electron, respectively.