采用恒温超声和低温退火两步法成功地合成了钾掺杂9-甲基蒽的分子晶体。直流磁化率测量结果表明合成的样品在1.8~300 K温度范围内表现为居里–外斯行为，且每个分子具有0.2~0.3 μB的磁矩。结合X-射线衍射和第一性原理计算结果发现，掺杂材料的晶体结构具有P21空间群，且钾和9-甲基蒽的摩尔比为1:1。电子结构计算和拉曼光谱测试表明局域磁矩的产生是由于钾将4s电子转移到了碳的2p轨道上。该研究工作对碱金属掺杂有机分子晶体的合成和理解其物理特性具有重要的借鉴作用。
Potassium-doped 9-methylanthracene is successfully synthesized by using a two-step synthesis method—ultrasound treatment and low temperature annealing. The dc magnetic measurements reveal that the synthesized materials exhibit a Curie-Weiss behavior in the temperature range of 1.8~300 K. The combination of measured XRD pattern and first-principle calculations identifies that the doped materials have a P21 space group and a mole ratio of 1:1 between potassium and 9-methylanthracene. Both the calculated electronic structure and the measured Raman spec-trum indicate that the formation of local moment is due to the transfer of K-4s electron to C-2p orbital. This study is useful for the synthesis of alkali-metal-doped organic molecular crystals and for understanding their physical properties.