Civiš S, Krisilov A V, Ferus M, Nechaev I V, Kubelík P, Chernov V E, Zon B A
J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, Prague 8 18223, Czech Republic.
Zhukovsky & Gagarin Air Force Academy, 394064 Voronezh, Russia.
Spectrochim Acta A Mol Biomol Spectrosc. 2021 Jun 5;254:119593. doi: 10.1016/j.saa.2021.119593. Epub 2021 Feb 19.
Endohedral fullerenes with paramagnetic encapsulated atoms are new magnetic materials of interest for numerous applications from medicine to quantum computers. An important phenomenon with endohedral fullerenes is the appearance of new vibrational frequencies not associated with empty fullerenes. The vibrational spectra of the lanthanide endohedral fullerenes La@C and Ce@C in various spin states are calculated using the density functional method. Most of the spectral lines lie in the 300-1600 cmrange, and their intensities change dramatically depending on the molecule's symmetry and spin state, which are determined by the encapsulated lanthanide atom. The average frequency shift of the carbon cage vibrations caused by spin transition is only 5 cm. The calculated frequencies of the coupled "metal-carbon cage" vibrations of the lanthanide endohedral fullerenes La@C and Ce@C in various spin states lie in the 10-170 cmrange. The computational results for both the frequencies and intensities of the metal-cage modes depend considerably on the spin state. The changes in these vibrational modes are due to the changes in the molecular symmetry and the metal-carbon bond lengths. Such dependence can be used as a basis for controlling the spin state of metallofullerenes by measuring the vibration frequencies in the far-infrared zone, which could be important for nanoelectronics and quantum informatics.
含有顺磁性包封原子的内嵌富勒烯是一类新型磁性材料，在从医学到量子计算机等众多领域都有应用前景。内嵌富勒烯的一个重要现象是出现了与空富勒烯无关的新振动频率。利用密度泛函方法计算了处于不同自旋态的镧系内嵌富勒烯La@C和Ce@C的振动光谱。大多数谱线位于300 - 1600厘米范围，其强度会根据分子的对称性和自旋态发生显著变化，而分子的对称性和自旋态由包封的镧系原子决定。自旋跃迁引起的碳笼振动平均频率偏移仅为5厘米。计算得到的处于不同自旋态的镧系内嵌富勒烯La@C和Ce@C的“金属 - 碳笼”耦合振动频率位于10 - 170厘米范围。金属 - 笼模式的频率和强度的计算结果在很大程度上取决于自旋态。这些振动模式的变化是由于分子对称性和金属 - 碳键长度的改变。这种依赖性可作为通过测量远红外区的振动频率来控制金属富勒烯自旋态的基础，这对纳米电子学和量子信息学可能具有重要意义。
