Department of Chemistry, Brown University, Providence, RI 02912 (USA).
Angew Chem Int Ed Engl. 2014 Feb 24;53(9):2464-8. doi: 10.1002/anie.201310323. Epub 2014 Jan 29.
Molecules with large enough dipole moments can bind an electron by the dipole field, which has little effect on the molecular core. A molecular anion can be excited to a dipole-bound state, which can autodetach by vibronic coupling. Autodetachment spectroscopy of a complex anion cooled in a cryogenic ion trap is reported. Vibrational spectroscopy of the dehydrogenated uracil radical is obtained by a dipole-bound state with partial rotational resolution. Fundamental frequencies for 21 vibrational modes of the uracil radical are reported. The electron affinity of the uracil radical is measured accurately to be 3.4810±0.0006 eV and the binding energy of the dipole-bound state is measured to be 146±5 cm(-1). The rotational temperature of the trapped uracil anion is evaluated to be 35 K.
具有足够大偶极矩的分子可以通过偶极场结合电子，这对分子核心几乎没有影响。分子阴离子可以被激发到偶极束缚态，通过振子耦合可以自动分离。报道了在低温离子阱中冷却的复杂阴离子的自动分离光谱。通过具有部分旋转分辨率的偶极束缚态获得了去氢尿嘧啶自由基的振动光谱。报道了尿嘧啶自由基的 21 个振动模式的基频。准确测量了尿嘧啶自由基的电子亲和能为 3.4810±0.0006 eV，偶极束缚态的结合能为 146±5 cm(-1)。捕获的尿嘧啶阴离子的旋转温度评估为 35 K。
