کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9804147 | 1516479 | 2005 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Structural stability of alkali boron tetrahydrides ABH4 (A = Li, Na, K, Rb, Cs) from first principle calculation
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
فلزات و آلیاژها
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Structural stability of alkali boron tetrahydrides ABH4 (A = Li, Na, K, Rb, Cs) from first principle calculation Structural stability of alkali boron tetrahydrides ABH4 (A = Li, Na, K, Rb, Cs) from first principle calculation](/preview/png/9804147.png)
چکیده انگلیسی
The ground-state crystal structures of the boron hydride series ABH4 (A = Li, Na, K, Rb, Cs) have been established from first principle projected-augmented plane-wave calculations by considering different possible structural arrangements and subjecting the test structures to structural relaxations. LiBH4 crystallizes with orthorhombic symmetry (KGaH4-type; Pnma), NaBH4, KBH4, and RbBH4 with tetragonal symmetry (γ-NaBH4-type; P42/nmc), and CsBH4 in another tetragonal space group (β-NaBH4-type; P4¯21c). A possible reason for the transitions from lower- to higher-symmetric structures along the series has been advanced. The theoretically derived positional parameters for LiBH4 gives an almost ideal tetrahedral configuration for the [BH4]â complex whereas the experimental results show that these units are strongly distorted. The theoretically derived structures for KBH4, RbBH4, and CsBH4 differ appreciably from the experimentally established low-temperature structures. From total-energy calculations it seems that syntheses under appropriate pressure and temperature conditions may be able to generate a number of metastable phases of the ABH4 series. The density-of-states characteristics reveal that all these ABH4 compounds exhibit insulating behavior with band gaps varying between 5.5 and 7.0âeV.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Alloys and Compounds - Volume 387, Issues 1â2, 25 January 2005, Pages 97-104
Journal: Journal of Alloys and Compounds - Volume 387, Issues 1â2, 25 January 2005, Pages 97-104
نویسندگان
P. Vajeeston, P. Ravindran, A. Kjekshus, H. Fjellvåg,