Experimental and theoretical study on Raman spectra of magnesium fluoride clusters and solids.
Experimental and theoretical study on Raman spectra of magnesium fluoride clusters and solids.
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DOI：
10.1063/1.4765700
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发表时间：
2012-11
期刊：
影响因子：
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通讯作者：
S. Neelamraju;Andreas Bach;J. C. Schön;Daniel Fischer;M. Jansen
中科院分区：
文献类型：
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作者：
S. Neelamraju;Andreas Bach;J. C. Schön;Daniel Fischer;M. Jansen
在这项研究中，拉曼和红外光谱的大量异构体的MgF（2）团簇和可能的块体多晶型MgF（2）的计算和比较与实验数据观察到使用低温原子束沉积。从早期的工作中获得了大量的多晶型物，而中性（MgF（2））（n）（n = 1-10）团簇和带电团簇（直到三聚体阴离子和阳离子，分别为（Mg（3）F（7））（-）和（Mg（3）F（5））（+））的团簇修饰在本工作中通过使用模拟退火的全球能量景观探索来确定。这些理论计算得到了MgF（2）的气相和沉积膜的实验研究的补充，所述MgF（2）的气相和沉积膜是在用于合成MgF（2）体相的低温原子束沉积装置中产生的。MgF（2）蒸气和膜分别通过嵌入Ar基质中的MgF（2）气相物质和沉积在冷却衬底上的MgF（2）膜的拉曼光谱来表征。我们发现，在气相中，有单体和二聚体和带电物种将存在于我们的实验装置。此外，结果表明，在非晶块体MgF（2）中，金红石状域的存在和MgF（2）团簇类似于在基质中。最后，在约800 cm（-1）处的峰与具有连接到三配位Mg原子的悬挂氟原子的簇的A（g）模式在相同的范围内，表明这种悬挂键也存在于无定形MgF（2）中。
In this study, the Raman and IR spectra of a large number of isomers of MgF(2) clusters and of possible bulk polymorphs of MgF(2) are calculated and compared with experimental data observed using a low-temperature atom beam deposition. The bulk polymorphs were taken from earlier work, while the cluster modifications for the neutral (MgF(2))(n) (n = 1-10) clusters and charged clusters (up to the trimer anion and cation, (Mg(3)F(7))(-) and (Mg(3)F(5))(+), respectively) are determined in the present work by global energy landscape explorations using simulated annealing. These theoretical calculations are complemented by an experimental study on both the vapor phase and the deposited films of MgF(2), which are generated in a low-temperature atom beam deposition setup for the synthesis of MgF(2) bulk phases. The MgF(2) vapor and film are characterized via Raman spectroscopy of the MgF(2) gas phase species embedded in an Ar-matrix and of the MgF(2)-films deposited onto a cooled substrate, respectively. We find that, in the vapor phase, there are monomers and dimers and charged species to be present in our experimental setup. Furthermore, the results suggest that in the amorphous bulk MgF(2), rutile-like domains are present and MgF(2) clusters similar to those in the matrix. Finally, peaks at about 800 cm(-1), which are in the same range as the A(g) modes of clusters with dangling fluorine atoms connected to three-coordinated Mg atoms, indicate that such dangling bonds are also present in amorphous MgF(2).