کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5416708 | 1506896 | 2010 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Theoretical study of hydration models of trivalent rare-earth ions using model core potentials
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
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چکیده انگلیسی
We performed geometry optimization calculations and ab initio molecular dynamics calculations for hydration models of trivalent ions, Y3+, La3+, Gd3+, and Lu3+, by using molecular orbital calculations to examine the so-called gadolinium break. The geometry optimization calculations revealed that the M-O distances of Y(H2O)83+, Lu(H2O)83+, and La(H2O)93+ calculated at the MP2 level were 2.39Â Ã
, 2.36Â Ã
, and 2.63Â Ã
, respectively, which agreed well with observed values. The calculated Gd-O distance (2.44Â Ã
) of Gd(H2O)83+ also agrees reasonably well with the existing observed values. The differences in the M-O distances arise from the differences in the ionic radii. When the coordination number increased, the degree of decrease in the M-O binding energies per bond (B.E.) occurred in the following order: La3+Â <Â Gd3+Â <Â Y3+Â <Â Lu3+. This order is consistent with the order of the ionic radii's inverse. In ab initio molecular dynamics calculations, by using the Y(H2O)243+ model we could realize the hydration structure where eight water molecules are located around the Y3+ ion. By using the bigger model of La(H2O)643+, the experimentally suggested structure coordinated by nine water molecules was reproduced.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure: THEOCHEM - Volume 949, Issues 1â3, 15 June 2010, Pages 28-35
Journal: Journal of Molecular Structure: THEOCHEM - Volume 949, Issues 1â3, 15 June 2010, Pages 28-35
نویسندگان
Takayuki Fujiwara, Hirotoshi Mori, Yuji Mochizuki, Hiroshi Tatewaki, Eisaku Miyoshi,