Density functional theory is demonstrated to reproduce the C-13 and B-11 NMR chemical shifts of icosahedral boron carbides with sufficient accuracy to extract previously unresolved structural information from experimental NMR spectra. B4C can be viewed as an arrangement of 3-atom linear chains and 12-atom icosahedra. According to our results, all the chains have a CBC structure. Most of the icosahedra have a B11C structure with the C atom placed in a polar site, and a few percent have a B-12 structure or a B10C2 structure with the two C atoms placed in two antipodal polar sites.
Atomic structure of icosahedral B4C boron carbide from a first principles analysis of NMR spectra / Mauri, F; Vast, N; Pickard, Cj. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 87:8(2001). [10.1103/PhysRevLett.87.085506]
Atomic structure of icosahedral B4C boron carbide from a first principles analysis of NMR spectra
Mauri, F;
2001
Abstract
Density functional theory is demonstrated to reproduce the C-13 and B-11 NMR chemical shifts of icosahedral boron carbides with sufficient accuracy to extract previously unresolved structural information from experimental NMR spectra. B4C can be viewed as an arrangement of 3-atom linear chains and 12-atom icosahedra. According to our results, all the chains have a CBC structure. Most of the icosahedra have a B11C structure with the C atom placed in a polar site, and a few percent have a B-12 structure or a B10C2 structure with the two C atoms placed in two antipodal polar sites.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
