We have carried out optical-absorption and reflectance measurements at room temperature in single crystals of AWO4 tungstates (A = Ba, Ca, Cd, Cu, Pb, Sr, and Zn). From the experimental results their band-gap energy has been determined to be 5.26 eV (BaWO4), 5.08 eV (SrWO4), 4.94 eV (CaWO4), 4.15 eV (CdWO4), 3.9-4.4 eV (ZnWO4), 3.8-4.2 eV (PbWO4), and 2.3 eV (CuWO4). The results are discussed in terms of the electronic structure of the studied tungstates. It has been found that those compounds where only the s electron states of the A2+ cation hybridize with the O 2p and W 5d states (e.g BaWO4) have larger band-gap energies than those where also p, d, and f states of the A2+ cation contribute to the top of the valence band and the bottom of the conduction band (e.g. PbWO4). The results are of importance in view of the large discrepancies existent in prevoiusly published data.
Compositional dependence of anomalous thermal expansion in perovskite-like ABX3 formates
利用变温X射线粉末衍射测量研究了组成为[Al][MII（HCOO）3]（A =烷基铵阳离子; M =八面体配位的二价金属）的19种不同类钙钛矿金属有机框架（MOF）的热膨胀行为的组成依赖性。虽然所有的系统基本上表现出相同类型的热机械响应-无论其特定的结构细节-这种响应的大小被证明是AI和MII阳离子半径的函数，以及AI的分子各向异性。大型MII和小型AI的灵活性最大化，而AI的形状对框架铰链的方向有影响。
Pressure induced structural transitions, coordination crossover, and optoelectronic response in divalent metavanadate CaV$_2$O$_6$
Indian Institute of Science Education and Research Kolkata（印度科学教育研究学院加尔各答分校）；National Centre for High-Pressure Studies（高压研究中心）；IMPMC, Sorbonne Université（巴黎第六大学地球物理学研究所）；Beijing Academy of Quantum Information Sciences（北京量子信息科学研究院）；Deutsches Elektronen Synchrotron（德国电子同步辐射中心）
