PO2自由基的光谱常数和非谐力场的理论研究

利用B3PW91、B3LYP和B3P86方法以及cc-pvQz和6-311++G(3df,3pd)基组计算了PO2自由基的光谱常数。先将计算的平衡几何结构、转动常数、谐频和基频、四次离心畸变常数和六次离心畸变常数与已有的相应实验或理论数据进行了比较。在此基础上，从理论上预测了非谐性常数、振转相互作用常数、科里奥利耦合常数、三次和四次力常数。计算结果表明，B3PW91/G理论水平得到的PO2自由基的光谱常数是可靠的。

Theoretical study of spectroscopic constants and anharmonic force field of PO2 free radical

The spectroscopic constants of the PO2 free radical are calculated by B3PW91, B3LYP and B3P86 methods employing two basis sets, 6-311++G(3df, 3pd) and cc-pvQz, respectively. The computed equilibrium geometries, rotational constants, harmonic frequencies, fundamental frequencies, quartic and sextic centrifugal distortion constants are compared with the corresponding experimental or previous theoretical values. The anharmonic constants, vibration-rotation interaction constants, coriolis coupling constants and cubic and quartic force constants are also predicted. The calculated results show that the B3PW91/G results are reliable.