共查询到20条相似文献,搜索用时 31 毫秒
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A theoretical method for investigating the inter-relation between the molecular structure and electronic structure has been established on the basis of the 252×252 complete energy matrices for a 3d5 configuration ion in a tetragonal ligand field. By means of this method, which is independent of the X-ray diffraction, the local structure of the paramagnetic Mn2+ ion in perovskite fluorides A2MF4 (A=K, Rb; M=Zn, Mg, Cd) are determined directly by analyzing the EPR spectrum of octahedral Mn2+ center in A2MF4 crystals and the optical absorption spectrum of the (MnF6)4− cluster. It is shown that, comparing with the octahedral cubic structure, the local micro-structure in the vicinity of Mn2+ displays an elongated distortion when and a compressed distortion when , and ΔR vs. as well as ΔR vs. in the distortion region is, respectively, approximately linear. Simultaneously, the theoretical zero-field-splitting parameters , and are in good agreement with the experimental values. 相似文献
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Qinghua Zeng 《Journal of luminescence》2003,101(3):167-174
The temperature-dependent luminescence of Sm2+ ions in MBPO5 was studied. At low temperature, Sm2+ in this series shows 4f6→4f6 luminescence with only a single emission line observed for the transition, revealing that only one crystallographic cationic site is available for Sm2+ in all the hosts. With increasing temperature, the emission intensity of the transition increases whereas that of the transitions decreases. The transitions of Sm2+ were observed in BaBPO5 and its intensity increases with increasing temperature. At , a broad band of the 4f55d→4f6 luminescent transition of Sm2+ in SrBPO5 and BaBPO5 with maximum at appears due to the thermal population. The lifetime of the transition was recorded at different temperatures, showing a single exponential decay for Sm2+ in SrBPO5 and BaBPO5 but a non-single-exponential decay in CaBPO5. 相似文献
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P. VingerhoetsK.T. Flanagan J. BillowesM.L. Bissell K. BlaumB. Cheal M. De RydtD.H. Forest Ch. GeppertM. Honma M. KowalskaJ. Krämer K. KreimA. Krieger R. NeugartG. Neyens W. Nörtershäuser J. PapugaT.J. Procter M.M. RajabaliR. Sánchez H.H. StrokeD.T. Yordanov 《Physics letters. [Part B]》2011,703(1):34-39
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Noriko Akutsu 《Applied Surface Science》2009,256(4):1205-1209
We present the restricted solid-on-solid (RSOS) model with the inter-ledge interaction of the point contact type (p-RSOS model). We have made detailed calculation of the Andreev free energy , which is similar to the equilibrium crystal shape (ECS) z=z(x,y), and the surface gradient as the function of the Andreev field . From the calculated and , we have obtained the vicinal surface free energy . The inter-ledge attraction between adjacent steps affects the surface free energies in the equilibrium, and causes the first-order transition on the profile of ECS at low temperature. The inter-ledge attraction also destabilizes the regular train of steps. We also have obtained the thermal step bunching. 相似文献