采用密度泛函方法(B3P86)对Fe2分子结构进行了优化.计算结果中未观察到自旋污染,基态波函数与高态波函数并未混杂,结果表明,Fe2中有8个未配对电子,这些电子空间分布不同和自旋平行产生的自旋极化效应,使Fe2能量最低.计算结果表明,Fe2分子的基态是9∑+g,并非7△u,进而表明Fe2的自旋平行效应比电子自旋配对效应要强.计算得到该分子基态的二阶、三阶和四阶力常数分别为1.4115×10-2aJm2、-37.1751×103 aJm3和98.7596×104 aJm4;光谱数据ωexe、Be、αe分别为0.3522、0.03450.4963×10-4 cm-1;离解能为3.5522 eV,平衡键长为0.2137 nm,振动频率为292.914 cm-1;并得到了Murrel-Sorbie函数.%Density functional method (B3p86) was used to optimize the structure of the molecule Fe2. The result showed that the ground electronic state for the molecule Fe2 is nonet state instead of septet state, which indicates that there is a spin polarization effect in the molecule Fe2, i.e., in which there are 8 parallel spin electrons.In this case, the number of the unpaired d-orbit electrons is the largest, and these electrons occupy different spatial orbitals so that the energy of the molecule Fe2 is minimized. Meanwhile, the spin pollution was not found because the wave functions of the ground state do not mix with those of the higher energy states. In addition, the Murrell-Sorbie potential functions with the parameters for the ground electronic state and other exited electronic states of the molecule Fe2 were derived. The dissociation energy, equilibrium bond length and the vibration frequency for the ground electronic state of the molecule Fe2 are 3.5522 eV, 0.2137 nm and 292.914 cm-1, respectively. Its force constants f2, f3 and f4 are 1.4115×102 a Jm2, -37.1751×103aJm3 and 98.7596× 104 a Jm4, respectively. The other spectroscopic parameters ωexe, Be and αe for the ground electronic state of Fe2 are 0.3522, 0.0345 and 0.4963× 10-4 cm-1, respectively.
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