24小时热门版块排行榜

返回列表

yufenfei3002

金虫 (小有名气)

应助: 17 (小学生)
金币: 1103.3
散金: 10
红花: 4
帖子: 220
在线: 117.6小时
虫号: 589612
注册: 2008-08-29
专业: 无机非金属类光电信息与功

[求助] GSAS中Polarization Fraction的意义是什么？

在看Lachlan Cranswick 和 Ian Swainson写的GSAS的教程，里面有一段话看不懂，求高手指点！

在创建GSAS Instrument Parameter file的时候（Powder -- Instedit -- Polarization Fraction）
具体见附件。

附件中的这段话看不明白，求指点。

A POLA value of 0.911. ( IPOLA should be set to 1 which defines the use of the Azaroff function, but currently there is not an option to do this in the Instedit screen, so it needs to be set in the EXP file during refinement). Paraphrasing a note from Bob von Dreele, “IPOLA=1 is in there to match the "traditional" Azaroff function for diffracted beam monochromators. The IPOLA=0 function is my adaption so that POLA is the polarized fraction. POLA=0.50 for no polarization and POLA=1.0 for perfect polarization nearly realized in synchrotron radiation & vertical diffraction.”. Polarization fraction can be calculated, but it can be good to determine this experimentally by running a suitable phase such as cubic Y2O3 from the lowest to highest angle of the diffractometer – e.g., 5 to 150 degrees 2-theta).

回复此楼