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Short‐Range Structure of Yttrium Alumino‐Silicate Glass for Cancer Radiotherapy: Car–Parrinello Molecular Dynamics Simulations
Author(s) -
Christie Jamieson K.,
Tilocca Antonio
Publication year - 2010
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.200980081
Subject(s) - yttrium , materials science , silicate , molecular dynamics , natural bond orbital , chemical physics , amorphous solid , silicon , mineralogy , chemical engineering , oxide , crystallography , density functional theory , metallurgy , chemistry , computational chemistry , engineering
We present Car–Parrinello molecular dynamics (CPMD) simulations of yttrium alumino‐silicate (YAS) glass. Alumino‐silicate glass microspheres are used as vectors of yttrium radioisotopes in cancer radiotherapy; understanding in detail how yttrium is bound within the glass network is important to control the unwanted release of radioactive yttrium in the bloodstream. Our simulations, focused on a specific composition relevant to practical applications, show that silicon and aluminum form a disordered glass network, where Si is mainly four‐coordinated, whereas, Al is mainly four‐ and five‐coordinated. Yttrium cations have a network‐modifying role, disrupting the alumino‐silicate network by breaking Si(Al)O bonds and coordinating the resulting non‐bridging oxygens (NBO). The local environment of yttrium in the glass turns out to be rather flexible: between five and eight oxygen atoms, with a marked predominance of NBO, are found coordinated to a central Y cation, leading to a corresponding broad and multimodal distribution of OYO angles.