The only stable state of O2- is the X 2Πg ground state and it (still!) has an adiabatic electron detachment energy of 0.45 eV
The only stable state of O2- is the X 2Πg ground state and it (still!) has an adiabatic electron detachment energy of 0.45 eV
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DOI：
10.1021/jp0357323
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发表时间：
2003-10-16
影响因子：
2.9
通讯作者：
Lineberger, WC
中科院分区：
文献类型：
--
作者：
Ervin, KM;Anusiewicz, W;Lineberger, WC
O-2（-）的紫外光电子能谱显示出从X（2）Pi（j）（J = 3/2和1/2）自旋轨道态到中性O-2的三个低电子态（X 3 Sigma（g）（-），a（1）Delta（g），B（1）Sigma（g）（+））的29个分辨振动跃迁。一个弗兰克-康登模拟，使用中性氧状态的既定分子常数，匹配光谱中的每一个观察到的功能。0-0原点跃迁被明确指定，产生电子亲和力EA（0）（O-2）= 0.448 +/- 0.006 eV。计算得到的键离解能为D-0（O-2（-））= 395.9 +/-0.6kJ/mol。在CCSD（T）/aug-cc-pVTZ水平上用耦合团簇理论计算了O-2和O-2（-）在基态和两个激发态的电子束缚区和非束缚区的势能曲线。稳定化方法被用来表征的阴离子曲线在键长，其电子能量位于基态中性以上。计算结果证实O-2（-）X（2）Pi（g）基态是热力学稳定的，但O-2（-）的最低电子激发态（a（4）Sigma（u）（-）和A（2）Pi（u））相对于电子脱离是热力学不稳定的.计算结果表明，阴离子双四重态分裂为T-e（a（4）Sigma（u）（-））- T-e（X（2）Pi（g））= 2.40 eV，第一激发双重态分裂为T-e（A（2）Pi（u））- Te（X（2）Pi（g））= 3.39 eV。在T-e（A（2）Pi（u））- Te（X（2）Pi（g））= 3.39 eV的能量下。这些观察结果与O-2上的电子散射和其他实验数据一致，并且它们尖锐地反驳了最近对电子捕获检测器实验的解释，即EA（O-2）近似于1 eV，O-2（-）具有低于中性基态最小值的多个激发态，并且双重四重态分裂为0.12 eV [Chen，E. S.的; Chen，中国山茱萸E. C. M. J. Phys. Chem. A 2003，107，169.]。
The ultraviolet photoelectron spectrum Of O-2(-) exhibits 29 resolved vibronic transitions to the three low-lying electronic states of neutral O-2 (X 3Sigma(g)(-), a (1)Delta(g), b (1)Sigma(g)(+)) from the X (2)Pi(j) (J = 3/2 and 1/2) spin-orbit states of the anion. A Franck-Condon simulation, using the established molecular constants of the neutral oxygen states, matches every observed feature in the spectrum. The 0-0 origin transition is unambiguously assigned, yielding the electron affinity EA(0)(O-2) = 0.448 +/- 0.006 eV. The derived bond dissociation energy is D-0(O-2(-)) = 395.9 +/- 0.6 kJ/mol. Coupled-cluster theory at the CCSD(T)/aug-cc-pVTZ level is used to determine the potential energy curves Of O-2 and Of O-2(-) in its ground state and two excited states, in both the electronically bound and unbound regions. Stabilization methods are employed to characterize the anion curves at bond lengths where their electronic energies lie above that of the ground-state neutral. The calculations confirm that the O-2(-) X (2)Pi(g) ground state is adiabatically stable, but the lowest electronically excited states Of O-2(-) (a (4)Sigma(u)(-) and A (2)Pi(u)) are adiabatically unbound with respect to electron detachment. The calculations predict the anionic doublet-quartet splitting to be T-e(a (4)Sigma(u)(-)) - T-e (X (2)Pi(g)) = 2.40 eV and the first excited doublet at an energy of T-e(A (2)Pi(u)) - Te(X (2)Pi(g)) = 3.39 eV. at an energy of T-e(A (2)Pi(u)) - Te(X (2)Pi(g)) = 3.39 eV. These observations are consistent with electron scattering on O-2 and other experimental data, and they sharply refute recent interpretations of electron-capture detector experiments that EA(O-2) approximate to 1 eV, that O-2(-) has multiple excited states below the neutral ground-state minimum, and that the doublet-quartet splitting is 0.12 eV [Chen, E. S.; Chen, E. C. M. J. Phys. Chem. A 2003, 107, 169.].