3He NMR：从自由气体到富勒烯的包封。

3He NMR: from free gas to its encapsulation in fullerene.

机构信息

Faculty of Chemistry, University of Opole, 48, Oleska Street, 45-052, Opole, Poland.

出版信息

Magn Reson Chem. 2013 Aug;51(8):463-8. doi: 10.1002/mrc.3972. Epub 2013 Jun 5.

Abstract

The (3)He nuclear magnetic shieldings were calculated for single helium atom, its dimer, simple models of fullerene cages (He@Cn), and single wall carbon nanotubes. The performances of several levels of theory (HF, MP2, DFT-VSXC, CCSD, CCSD(T), and CCSDT) were tested. Two sets of polarization-consistent basis sets were used (pcS-n and aug-pcS-n), and an estimate of (3)He nuclear magnetic shieldings in the complete basis set limit using a two-parameter fit was established. Theoretical (3)He results reproduced accurately previously reported theoretical values for helium gas, dimer, and helium probe inside several fullerene cages. Excellent agreement with experimental values was achieved. (3)He nuclear magnetic shieldings of single helium atom approaching various points of benzene ring were tested, and an impact of (3)He confinement within fullerene cages of different size on the (3)He chemical shift was determined.

摘要

（3）氦核磁共振屏蔽被计算为单个氦原子、其 dimer、富勒烯笼（He@Cn）的简单模型和单壁碳纳米管。测试了几种理论水平（HF、MP2、DFT-VSXC、CCSD、CCSD(T)和 CCSDT）的性能。使用了两套极化一致基组（pcS-n 和 aug-pcS-n），并使用双参数拟合建立了在完全基组极限下（3）氦核磁共振屏蔽的估计。理论（3）氦结果准确地再现了先前报道的氦气、 dimer 和氦探针在几个富勒烯笼内的理论值。与实验值取得了极好的一致性。测试了单个氦原子接近苯环各个点的（3）氦核磁共振屏蔽，确定了不同大小的富勒烯笼内（3）氦的限制对（3）氦化学位移的影响。