Head Ashley R, Tsyshevsky Roman, Trotochaud Lena, Eichhorn Bryan, Kuklja Maija M, Bluhm Hendrik
Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
J Phys Chem A. 2016 Mar 31;120(12):1985-91. doi: 10.1021/acs.jpca.6b01098. Epub 2016 Mar 22.
Dimethyl methylphosphonate (DMMP) is one of the most widely used molecules to simulate chemical warfare agents in adsorption experiments. However, the details of the electronic structure of the isolated molecule have not yet been reported. We have directly probed the occupied valence and core levels using gas phase photoelectron spectroscopy and the unoccupied states using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Density functional theory (DFT) calculations were used to study the electronic structure, assign the spectral features, and visualize the molecular orbitals. Comparison with parent molecules shows that valence and core-level binding energies of DMMP follow trends of functional group substitution on the P center. The photoelectron and NEXAFS spectra of the isolated molecule will serve as a reference in studies of DMMP adsorbed on surfaces.
甲基膦酸二甲酯（DMMP）是吸附实验中模拟化学战剂使用最广泛的分子之一。然而，孤立分子的电子结构细节尚未见报道。我们使用气相光电子能谱直接探测了占据的价电子和核心能级，并使用近边X射线吸收精细结构（NEXAFS）光谱探测了未占据态。采用密度泛函理论（DFT）计算来研究电子结构、确定光谱特征并可视化分子轨道。与母体分子的比较表明，DMMP的价电子和核心能级结合能遵循P中心上官能团取代的趋势。孤立分子的光电子能谱和NEXAFS光谱将作为研究吸附在表面的DMMP的参考。
