溫馨提示：需求數(shù)量不同，價(jià)格不同。請(qǐng)聯(lián)系我們，確認(rèn)當(dāng)前新的報(bào)價(jià)！
FEFF是一個(gè)自洽的多重散射從頭計(jì)算XAS譜和電子結(jié)構(gòu)的軟件包。用于同時(shí)計(jì)算X射線吸收光譜和電子結(jié)構(gòu)。輸出包括擴(kuò)展的X射線吸收精細(xì)結(jié)構(gòu)（EXAFS），各種X射線吸收光譜（XAS）的全多次散射計(jì)算以及投影的局部密度（LDOS）。光譜包括邊緣結(jié)構(gòu)附近的X射線吸收（XANES），X射線自然和磁性圓二色性（XNCD和XMCD），自旋極化X射線吸收光譜（SPXAS和SPEXAFS），非共振X射線光譜（XES），X射線散射幅度（Thomson）和電子能量損失譜（EELS）。該代碼產(chǎn)生許多現(xiàn)代XAFS分析代碼中使用的散射振幅和相位，以及各種其他屬性。
FEFF 9：新版本是FEFF9（版本9.6）
FEFF 9具有各種新功能和選項(xiàng)。首先有幾個(gè)可以用FEFF 9計(jì)算的新的光譜，包括電子能量損失譜（EELS）和非共振非彈性X射線散射（NRIXS）。另外，還有各種改進(jìn)。這些包括;
（1）從頭開(kāi)始的 Debye-Waller因子;
（2）改善非彈性損失的治療;
（3）核心 - 空穴相互作用的改進(jìn)處理;
（4）用格林函數(shù)的k空間計(jì)算更精確地處理結(jié)晶體系。
（5）利用基于自洽的球型MT散射勢(shì)的實(shí)空間Green函數(shù)方法, 計(jì)算中考慮了polarizationdependence, core-hole efects,and local field corrections,et al.
（6）FEFF9增加了倒空間計(jì)算(周期邊界條件)
FEFF9附帶JFEFF GUI。
FEFF能夠提供如下的計(jì)算：
- 散射振幅: effective scattering amplitude；x-rayelastic scattering amplitude f = f0+f’+if ’’, includingThomson and anomalous parts
- 相移函數(shù) : Ø，effective scattering phase shift
- 平均自由程 : λ，mean free path
- 初始路徑長(zhǎng)：R0
- Deybe-Waller因子: σ
- feffnnnn:
- chi :
- …..
FEFF9的模塊結(jié)構(gòu)
輸入、輸出處理
原子勢(shì)計(jì)算
嵌入的原子勢(shì)計(jì)算
屏蔽效應(yīng)計(jì)算
ldos計(jì)算
截面和相移函數(shù)計(jì)算
全多重散射計(jì)算
求GT的跡
路徑計(jì)算
計(jì)算散射振幅和其它XAFS參數(shù)
計(jì)算指定的譜
計(jì)算多電子激發(fā)
計(jì)算eels
FEFF 8：
FEFF 8 通過(guò)包括自我一致的電勢(shì)計(jì)算來(lái)提供電荷轉(zhuǎn)移和更精確的費(fèi)米能級(jí)估計(jì)，改進(jìn)了FEFF的先前版本。它還包括完全多次散射計(jì)算，以改善XANES計(jì)算，其中多次散射擴(kuò)展可能無(wú)法收斂。FEFF 8可輸出角動(dòng)量投影狀態(tài)密度，x射線發(fā)射光譜和x射線散射振幅。FEFF 8.40的改進(jìn)簡(jiǎn)化了依賴于自旋的計(jì)算，并且可以包括對(duì)核心孔和局部場(chǎng)效應(yīng)的改進(jìn)處理。FEFF8現(xiàn)在包括JEFEFF，F(xiàn)EFF 8.4的圖形前端。
【英文介紹】
FEFF is an automated program for ab initio multiple scattering calculations of X-rayAbsorption Fine Structure (XAFS), X-ray Absorption Near-Edge Structure (XANES) andvarious other spectra for clusters of atoms. The code yields scattering amplitudes andphases used in many modern XAFS analysis codes, as well as various other properties.
FEFF is a software program used in x-ray absorption spectroscopy. It contains self-consistenr real space multiple-scattering code for simultaneous calculations of x-ray-absorption spectra and electronic structure. Output includes extended x-ray-absorption fine structure, full multiple scattering calculations of varioud x -ray absorption spectra and projected local densities of states. The spectra include x-ray absorption near edge structure, x-ray natural circular dichroism, and non-resonant x-ray emission spectra. Calculations of the x-ray scattering amplitude and spin dependent calcuations of x-ray magnetic circular dichrosim and spin polarized x-ray absorption spectra are also possible, but less automated.
FEFF 9: The newest version is FEFF9 (Version 9.6)
FEFF 9 has a variety of new features and options. First there are several newspectroscopies which can be calculated with FEFF 9, including electron energy lossspectra (EELS) and non-resonant inelastic x-ray scattering (NRIXS). In addition, there area variety of improvements. These include; (1) ab initio Debye-Waller factors; (2)improved treatment of inelastic losses; (3) an improved treatment of the core-holeinteraction; and (4) more accurate treatment of crystalline systems with k-spacecalculation of the Green's function. FEFF9 comes with the JFEFF GUI.
FEFF 8:
FEFF 8 improves over previous versions of FEFF by including self consistent calculationof potentials to provide charge transfer and a more accurate estimate of the Fermi level.It also includes full multiple scattering calculations to improve XANES calculations,where multiple scattering expansions can fail to converge. FEFF 8 can output theangular momentum projected density of states, x-ray emission spectra and x-rayscattering amplitudes. The improvements in FEFF 8.40 simplify spin-dependentcalculations and can include improved treatment of core-hole and local field effects.FEFF8 now includes JFEFF, a graphical front-end for FEFF 8.4.
