XPS系统软件操作指南

XPS系统软件操作指南
──MANUAL OF PERKIN ELMER PHI 5000C ESCA SYTEM
戴维林编
Edited by Dai Wei-Lin
（复旦大学化学系表面化学实验室）(Surf. Chem. Lab., Dept. of Chem., Fudan Univ.)
第一部分 数据采集软件—PHI系统
§1. 概述：
该系统通过PC137数据采集板把XPS数据和图谱存进计算机，支持软件为PHI系统。

PERKIN ELMER公司提供了多种版本的软件，从最初的DOS系统软件到如今的WINDOWS系统软件。

目前最常用的为VERSION2.0A版本。

VERSION1.2B也能使用。

该软件功能较强，可进行宽、窄扫描，多次录谱迭加，并可适应不同的能量分析器，还可在谱图上定出峰位、半峰宽，并且可进行平滑化、微分等操作。

§2. 软件安装及初始化
将拷有PHI软件的软盘插入驱动器，键入命令：C:>install_A:_C:\phi SCASCD or CMASCD or SCAMCD↵
其中，_代表空格；A: 指源程序盘；C:\phi为安装后的子目录；SCASCD、 CMASCD和SCAMCD分别指不同的能量分析器。

安装后，可通过简单的指令使其窗口化，即可直接在WINDOWS下用鼠标来操作。

下面主要讲一些VERSION2.0A的具体格式化过程：
进入PHI后，屏幕上为一排指令，FILE、CONTROL、PARMS、DATA和 WINDOW。

首先键击CONTROL进入CONFIGURE。

选择所需的指令，如本实验室的各项指令为：
SCA/SCD、MODEL80-365A、MODEL137 TIMER、EXTENTED（LENS TYPE）。

然后储存这些参数（用SAVE 指令）。

再键击FILE，击OPEN，查看C:\phi下各•PHI文件。

1) 将MODEL 137 COUNTER文件中INPUT SELECT置于ECL IN 1[PC]，COUNT UP/DOWN置于UP。

2)将SCA CONTROL、MODEL 80-365 A内各项进行更改。

WORK FUNCTION（功函数）置于测定值（用Ag、Au 或Cu定标），DRLL PORT TYPE置于MODEL 137，MULTIPLIER（VOLTS）置于测定值（这在EMS条下会作解释），LENS 3 MODE置于XPS MODE，别的条目最好不要动。

3) 将SCASCD中，各项设置成：FIXED ANALYZE TRANSMISION，WORK FUNCTION修改为所测值，PASS ENERGY置于所需值，一般为23.5eV，对信号弱的可置于46.95或93.90eV。

MULTIPLIER按（2）修改。

LENS 3 MODE 为XPS，WORKING DISTANCE置于 1.5 INCHES, SOURCE SELECTION置于SOURCE#1，ANODE可选Mg （#1）或Al（#2）。

4) 将SCAXPSR中各项设置成所需的条件，如REGION NAME可为各元素名，SWEEP NUMBER可设成5∼30次，TIME PERSTEP为100 MS,STEPSIZE为0.1∼1eV。

随所需
扫描的宽度及精度而定。

5) EMS中高压的确定：这是确定电子倍增器高压的必须过程。

首先将仪器全部打开，进入扫谱状态，然后，打开EMS 文件，执行EXCUTE，观察屏幕上的图形，一般为膝形，取刚进入平稳段的电压值为MUTIPLIER所需高压值。

新仪器为1600V, 以后慢慢会往高电压处上升，直到2400V。

此时，就该更换电子倍增器了。

总之，应将有关的•phi文件中与特定的能量分析器相关的全部设置成所需的参数，方可进入下一阶段。

§3. 通用的扫描步骤：
1)进入PHI系统。

2)打开COUNT137.phi，改DOWN为UP。

3)进入SCASCD.phi，更改所需参数（主要改功函数[WORK FUNCTION]; 扫描模式FAT or FRR; 通能PASS ENERGY; 阳极靶Mg or Al）。

注意：更改Mg靶为Al靶时，只用更改ANODE #1为ANODE #2即可，其能量1253.6 eV将会自动变为1486.6eV.
4)进入SCAXPSR•phi更改各所需参数。

用鼠标加键盘即可完成对各参数的设置。

主要有REGION NAME改为所扫描的元素符号，如C、O、K等；SWEEP NUMBER改为所需值，宽扫描1~5次，窄扫描5~100次不等；TIME PERSTEP
一般为100MS； STEP SIZE宽扫描1eV, 窄扫描0.05~0.5eV 不等，视具体情况而定。

至于扫描区间，要改为所需区间，如碳（C）：280~300eV。

再更改所需模式，Kinetic Energy or Binding Energy。

如果要让计算机扫完一个元素后，接着扫第二个、第三个……，可击ADD REGION, 按上述步骤添加即可。

不过，这种方式建议不要采用。

因为妨碍以后的数据处理。

5)全部修改完，进入CONTROL, 击EXECUTE, 开始扫描。

待屏幕上呈现EXECUTION COMPLETE! 可击OK，然后击FILE, 进行文件存储工作。

一般存为•phi(save as)、•pcw(save as Matlab)或•asc(save as AscII)。

6)如需对曲线进行平滑，可按DATA内的SMOOTH，或用手按住“S”，并用鼠标箭头连击DATA，至满意为止。

7)存完一文件后，进入下一个元素的扫描。

§4. 总结
以上为最常用和最基本的操作方法，掌握后即可进行日常的采谱和处理工作。

如需进行一些高级动作，可请教这方面的专家或自己钻研PHI程序手册。

第二部分 数据处理软件──PHIMAT系统
§1. 概述
该软件主要进行•pcw文件的处理，可有多种功能，如：平滑、积分、迭加、差谱、谱峰解迭、峰位确定、半峰宽及峰面积的列表等。

基本上可完成对多种价态的分解、拟合，表面元素丰度的定量，等等。

一般来说，一台增强的386或更好的机型，内存8M的配置即可满足要求。

相对来说，还算比较方便。

§2.安装和初始化
1. 安装
该软件的安装极其简单，只需将“PHIMAT”安装盘插入驱动器，键入C:>INSTALL_B:_C:\PHIMAT↵。

注意：安装完毕务必重新启动计算机！！！
接下来再安装MATLAB软件，同样在驱动器中插入MATLAB安装盘，键入C:>INSTALL_B:_C:\MATLAB↵即可。

然后按照提示完成接下来的安装步骤。

最后，将其置入WINDOWS窗口，启动MATLAB↵，键入盘面的登录序号（SERIAL NUMBER），即告完成。

2. 初始化
必须对一些文件进行更改，方可使打印机正常工作。

（1）在C：根区下进入MATLAB\MATLAB>，更改PRINT z M。

C:\MATLAB\MATLAB>EDIT PRINT z M↵更改其中的打印机设置格式即可。

将文件中的“！GPP_METATMP_/DEPSD”一行改为：
EPSON打印机：!GPP_METATMP_/DEPSD_/FPRN
HP LASERJET: !GPP_METATMP_/DJET_/FPRN
HP DESKJET: !GPP_METATMP_/DDESK_/FPRN
EPSON LQ,DRAFT:!GPP_METATMP_/DLQD_/FPRN
EPSON LQ,FINAL: !GPP_METATMP_/DLQF_/FPRN
对特殊型号的打印机可参阅“MATLAB”一书1-31页进行修改。

（2） 在C：根区下进入MATLAB\BIN>，更改GPP z BAT。

C:\MATLAB\BIN>EDIT_GPP.BAT↵
更改所有的“PCGPP”为“GPP386”；更改PCGPP_%1_/DESD_/FPRN为GPP386_%1_/D*_/FPRN(注：*为参照（1）所改的对应于各打印机的参数。

)
§3.图谱解析
1. 基本命令
（1） OPEN_C:\FILES\****z PCW↵
对用PHI软件采集的数据，只要“SAVE AS MATLAB”，便可产生一个后缀为z PCW的文件。

此时可用“OPEN”打开。

同时要注意对打开的文件名前加上路径，即待处理之XPS文件所处的目录等。

（2） CLOSE↵、 CLOSE ALL↵分别为关闭当前的文件和所有打开的文件。

（3） EXP：为选取所需的范围，即横坐标上指定的能量区间。

如，EXP 150:170↵等。

（4） LINE↵：为对所选取的范围与零点拉基线，以便求面积。

（5） PEAKAREA↵：求XPS峰与所拉基线间的面积。

（6） TABLE↵：列出面积的具体数值。

（7） MERGE↵：对所打开的文件（必须具有相同的区间，步长，步进）进行迭加。

（8） DIS↵：显示所打开文件的XPS图谱。

（9） GRTIME_ *↵：定义图谱显示的时间。

*为数值时，代表显示的秒数；*为“KEY”时，表示任意键。

即只要敲击键盘上任何键即可停止显示。

（10） SUBMIN↵：使MERGE后的图谱进行等基线迭
加。

即将所有的图谱起点均定义在零点。

（11） SUBTRACT_ *↵：以某一图谱为本底，作差谱。

*代表本底图谱的序号。

比如，打开的文件共有3个，计算机将它们列为1、2和3号，如想作2、3号与1号的差谱，只要键入SUBTRACT_ 1↵即可。

（12） DELETE_ * ↵：删除某个文件。

*为文件号。

（13） DIR_ ***\***>↵：列出所选路径内的所有文件。

（14） LOAD_***\***z PCW↵:功能同“OPEN”。

（15） REOPEN_***\***z PCW↵:再次打开已打开之文件。

（16） SAVE↵：存储已处理或进行过各种变化的文件。

（17） FILES↵：选择所打开文件中的一个。

（18） PC137↵：设置所取文件来源为PC137板。

（19） PCW↵：设置所取文件来源为*z PCW文件。

（20） REGIONS↵：选择所需的区域（每个文件可由若干区域组成）。

（21） RENAME REGION↵：重命名所选区域。

（22） DTIME↵：显示时间和日期。

（23） EXIT↵：退出MATLAB。

（24） CURSOR↵：显示（用鼠标左键轻击）各点的能量、峰强度。

（25） LEFT↵：左半显示。

（26） RIGHT↵：右半显示。

（27） LOWER↵：下半显示。

（28） UPPER↵：上半显示。

（29） UL↵：上左显示。

（30） LR↵：下右显示。

（31） LL↵：左下显示。

（32） UR↵：左上显示。

2. 图谱解析
(1) open_c:\files\***.pcw↵
(2) cfsetup_**↵ (**为元素名称，C、N、Cu等。

)
在进入窗口命令后，可用鼠标来完成对以下各参数的确定：当确定新峰时，键击NEW（新峰）进入下一窗口：POSITION（峰位）/HEIGHT（峰高）、FWHM（半峰宽）、%GAUSSIAN（高斯函数在GAUSSIAN-LORENTZIAN函数中的百分比），其中TAIL LENGTH、TAIL SCALE、AREA LOCK和SEPARATION LOCK均为特殊处理命令，分别代表不对称峰拖尾长度、拖尾比例、峰面积锁定和各峰分别锁定。

一般用得不多，如特殊场合需要使用，可再详细研究其具体使用办法。

每完成一个新峰，均用DONE来结束。

然后继续开始另一峰的确定。

如果所分的峰被认为是不对称的，则应在SET PARAMETER中的FIT TYPE确定其为ASYMMETRIC GAUSSIAN-LORENTZIAN，如为纯粹的高
斯函数，则选择GAUSSIAN。

另外，亦可选择SET PARAMETER中的BACKGROUND TYPE、MULTIPLET LOCK和INTERATIONS等命令进行一些特殊处理。

而SELECT、EDIT和DELETE分别指对已有之峰（已经分好或直接继承上次的分峰结果）进行选择、编辑和删除等操作。

ABORT指放弃刚刚所进行的各种操作。

最后，用DONE来回到上一命令。

再次击DONE，退回到PHI>下。

（2） CURVEFIT_**↵。

对手动分的峰用计算机进行迭代，直至误差小到满意为止。

一般机器设置迭代次数为15次，如已经趋平，则一次即可停止。

否则，可继续运行CURVEFIT命令，直至满意为止。

（3） CFSUM↵。

显示分峰结果。

（4） PASS PRINT↵。

打印出所分之峰。

注：这里很需要一些技巧和经验，而且对各元素的峰形、半峰宽均要熟悉。

可根据不同的情况进行特殊处理，如不需CURVEFIT，亦不必强求。

因为迭代之后很可能面目全非，但此时打印出的包络线将为小圆圈而不是迭代后的虚线。

具体的细节可参考外文说明书。

§4. 小结
以上虽只是粗略的介绍了一些基本命令和操作，但用于一般的谱峰解迭和处理亦已足够。

日常使用最多的操作分别
为：
（1） 表面元素浓度的确定。

依据所测各元素特征峰的面积，采用元素灵敏度因子进行校正后，将所有的元素峰面积归一化，便可算出各元素所占的比例，亦即表面各元素的浓度。

这里要特别小心的是，不同元素不同能级的灵敏度因子是绝对不会相同的，千万不要搞错。

而且所测的值也只是相对比较精确，绝对误差可能较大（10~20%），所以，如需精确定量，最好采用已知浓度的标样进行标定。

（2） 由于软件功能所限，很难将许多图谱等间隔排列并进行比较。

不过，可以通过“SAVE AS ASCII”将XPS数据输入到SIGMAPLOT或ORINGIN等处理软件中处理来解决这一困难。

（3） 平常只要对一些对称峰（如C1s、O1s、Ag 3d5/2等）进行分峰处理即可。

如本身不对称的峰（如Fe 2p、Co 2p、Ni 2p等），则分峰即非易事。

需要足够的耐心和经验，否则谬之千里也！
总之，该手册不可能包罗一切，如有问题，请立即向这方面的专家请教或自己钻研原版的手册。

Using XPSPEAK Version 4.1 November 2000
Contents Page
Number XPS Peak Fitting Program for WIN95/98 XPSPEAK Version 4.1 (1)
Program Installation (1)
Introduction (1)
First Version (1)
Version 2.0 (1)
Version 3.0 (1)
Version 3.1 (2)
Version 4.0 (2)
Version 4.1 (2)
Future Versions (2)
General Information (from R. Kwok) (3)
Using XPS Peak (3)
Overview of Processing (3)
Appearance (4)
Opening Files (4)
Opening a Kratos (*.des) text file (4)
Opening Multiple Kratos (*.des) text files (5)
Saving Files (6)
Region Parameters (6)
Loading Region Parameters (6)
Saving Parameters (6)
Available Backgrounds (6)
Averaging (7)
Shirley + Linear Background (7)
Tougaard (8)
Adding/Adjusting the Background (8)
Adding/Adjusting Peaks (9)
Peak Types: p, d and f (10)
Peak Constraints (11)
Peak Parameters (11)
Peak Function (12)
Region Shift (13)
Optimisation (14)
Print/Export (15)
Export (15)
Program Options (15)
Compatibility (16)
File I/O (16)
Limitations (17)
Cautions for Peak Fitting (17)
Sample Files: (17)
gaas.xps (17)
Cu2p_bg.xps (18)
Kratos.des (18)
ASCII.prn (18)
Other Files (18)
XPS Peak Fitting Program for WIN95/98 XPSPEAK
Version 4.1
Program Installation
XPS Peak is freeware. Please ask RCSMS lab staff for a copy of the zipped 3.3MB file, if you would like your own copy
Unzip the XPSPEA4.ZIP file and run Setup.exe in Win 95 or Win 98.
Note: I haven’t successfully installed XPSPEAK on Win 95 machines unless they have been running Windows 95c – CMH.
Introduction
Raymond Kwok, the author of XPSPEAK had spent >1000 hours on XPS peak fitting when he was a graduate student. During that time, he dreamed of many features in the XPS peak fitting software that could help obtain more information from the XPS peaks and reduce processing time.
Most of the information in this users guide has come directly from the readme.doc file, automatically installed with XPSPEAK4.1
First Version
In 1994, Dr Kwok wrote a program that converted the Kratos XPS spectral files to ASCII data. Once this program was finished, he found that the program could be easily converted to a peak fitting program. Then he added the dreamed features into the program, e.g.
• A better way to locate a point at a noise baseline for the Shirley background calculations
• Combine the two peaks of 2p3/2 and 2p1/2
• Fit different XPS regions at the same time
Version 2.0
After the first version and Version 2.0, many people emailed Dr Kwok and gave additional suggestions. He also found other features that could be put into the program.
Version 3.0
The major change in Version 3.0 is the addition of Newton’s Method for optimisation
• Newton’s method can greatly reduce the optimisation time for multiple region peak fitting.
Version 3.1
1. Removed all the run-time errors that were reported
2. A Shirley + Linear background was added
3. The Export to Clipboard function was added as requested by a user • Some other minor graphical features were added
Version 4.0
Added:
1. The asymmetrical peak function. See note below
2. Three additional file formats for importing data
• A few minor adjustments
The addition of the Asymmetrical Peak Function required the peak function to be changed from the Gaussian-Lorentzian product function to the Gaussian-Lorentzian sum function. Calculation of the asymmetrical function using the Gaussian-Lorentzian product function was too difficult to implement. The software of some instruments uses the sum function, while others use the product function, so both functions are available in XPSPEAK.
See Peak Function, (Page 12) for details of how to set this up.
Note:
If the selection is the sum function, when the user opens a *.xps file that was optimised using the Gaussian-Lorentzian product function, you have to re-optimise the spectra using the Gaussian-Lorentzian sum function with a different %Gaussian-Lorentzian value.
Version 4.1
Version 4.1 has only two changes.
1. In version 4.0, the printed characters were inverted, a problem that was
due to Visual Basic. After about half year, a patch was received from Microsoft, and the problem was solved by simply recompiling the program
2. The import of multiple region VAMAS file format was added
Future Versions
The author believes the program has some weakness in the background subtraction routines. Extensive literature examination will be required in order to revise them. Dr Kwok intends to do that for the next version.
General Information (from R. Kwok)
This version of the program was written in Visual Basic 6.0 and uses 32 bit processes. This is freeware. You may ask for the source program if you really want to. I hope this program will be useful for people without modern XPS software. I also hope that the new features in this program can be adopted by the XPS manufacturers in the later versions of their software.
If you have any questions/suggestions, please send an email to me.
Raymund W.M. Kwok
Department of Chemistry
The Chinese University of Hong Kong
Shatin, Hong Kong
(852)-2609-6261
Tel:
Fax:(852)-2603-5057
rmkwok@.hk
email:
I would like to thank the comments and suggestions from many people. For the completion of Version 4.0, I would like to think Dr. Bernard J. Flinn for the routine of reading Leybold ascii format, Prof. Igor Bello and Kelvin Dickinson for providing me the VAMAS files VG systems, and my graduate students for testing the program. I hope I will add other features into the program in the near future.
R Kwok.
Using XPS Peak
Overview of Processing
1. Open Required Files
• See Opening Files (Page 4)
2. Make sure background is there/suitable
• See Adding/Adjusting the Background, (Page 8)
3. Add/adjust peaks as necessary
• See Adding/Adjusting Peaks, (Page 9), and Peak Parameters, (Page 11)
4. Save file
• See Saving Files, (Page 6)
5. Export if necessary
• See Print/Export, (Page 15)
Appearance
XPSPEAK opens with two windows, one above the other, which look like this:
• The top window opens and displays the active scan, adds or adjusts a background, adds peaks, and loads and saves parameters.
• The lower window allows peak processing and re-opening and saving data
Opening Files
Opening a Kratos (*.des) text file
1. Make sure your data files have been converted to text files. See the back
of the Vision Software manual for details of how to do this. Remember, from the original experiment files, each region of each file will now be a separate file.
2. From the Data menu of the upper window, choose Import (Kratos)
• Choose directory
• Double click on the file of interest
• The spectra open with all previous processing INCLUDED
Opening Multiple Kratos (*.des) text files
• You can open up a maximum of 10 files together.
1. Open the first file as above
• Opens in the first region (1)
2. In the XPS Peak Processing (lower) window, left click on 2 (second
region), which makes this region active
3. Open the second file as in Step 2, Opening a Kratos (*.des) text file,
(Page 4)
• Opens in the second region (2)
• You can only have one description for all the files that are open. Edit
with a click in the Description box
4. Open further files by clicking on the next available region number then
following the above step.
• You can only have one description for all the files that are open. Edit
with a click in the Description
box
• To open a file that has already been processed and saved using
XPSPEAK, click on the Open XPS button in the lower window. Choose directory and file as normal
• The program can store all the peak information into a *.XPS file for later
use. See below.
Box
Saving Files
1. To save a file click on the Save XPS button in the lower window
2. Choose Directory
3. Type in a suitable file name
4. Click OK
• Everything that is open will be saved in this file
• The program can also store/read the peak parameter files (*.RPA) so that you do not need to re-type all the parameters again for a similar spectrum.
Region Parameters
Region Parameters are the boundaries or limits you have used to set up the background and peaks for your files. These values can be saved as a file of the type *.rpa.
Note that these Region Parameters are completely different from the mathematical parameters described in Peak Parameters, (Page 11) Loading Region Parameters
1. From the Parameters menu in the upper window, click on Load Region
Parameters
2. Choose directory and file name
3. Click on Open button
Saving Parameters
1. From the Parameters menu in the XPS Peak Fit (Upper) window, click
on Save Region Parameters
2. Choose directory and file name
3. Click on the Save button
Available Backgrounds
This program provides the background choices of
• Shirley
• Linear
• Tougaard
Averaging
• Averaging at the end points of the background can reduce the time to find a point at the middle of a noisy baseline
• The program includes the choices of None (1 point), 3, 5, 7, and 9 point average
• This will average the intensities around the binding energy you select.
Shirley + Linear Background
1. The Shirley + Linear background has been added for sloping
backgrounds
• The "Shirley + Linear" background is the Shirley background plus a straight line with starting point at the low BE end-point and with a
slope value
• If the slope value is zero, the original Shirley calculation is used
• If the slope value is positive, the straight line has higher values at the high BE side, which can be used for spectra with higher
background intensities at the high BE side
• Similarly, a negative slope value can be used for a spectrum with lower background intensities at the high BE side
2. The Optimization button may be used when the Shirley background is
higher at some point than the signal intensities
• The program will increase the slope value until the Shirley background is below the signal intensities
• Please see the example below - Cu2p_bg.xps - which shows background subtraction using the Shirley method (This spectrum
was sent to Dr Kwok by Dr. Roland Schlesinger).
• A shows the problematic background when the Shirley background is higher than the signal intensities. In the Shirley calculation routine,
some negative values were generated and resulted in a non-
monotonic increase background
• B shows a "Shirley + Linear" background. The slope value was input by trial-and-error until the background was lower than the signal
intensities
• C was obtained using the optimisation routine
A slope = 0
B slope = 11
C slope = 15.17
Note: The background subtraction calculation cannot completely remove the background signals. For quantitative studies, the best procedure is "consistency". See Future Versions, (Page 2).
Tougaard
For a Tougaard background, the program can optimise the B1 parameter by minimising the "square of the difference" of the intensities of ten data points in the high binding energy side of the range with the intensities of the calculated background.
Adding/Adjusting the Background
Note: The Background MUST be correct before Peaks can be added. As with all backgrounds, the range needs to include as much of your peak as possible and as little of anything else as possible.
1. Make sure the file of interest is open and the appropriate region is active
2. Click on Background in the upper window
• The Region 0 box comes up, which contains the information about the background
3. Adjust the following as necessary. See Note.
• High BE (This value needs to be within the range of your data) • Low BE (This value needs to be within the range of your data)
NOTE: High and Low BE are not automatically within the range of your data. CHECK CAREFULLY THAT BOTH ENDS OF THE BACKGROUND ARE INSIDE THE EDGE OF YOUR DATA. Nothing will happen otherwise.
• No. of Ave. Pts at end-points. See Averaging, (Page 7)
• Background Type
• Note for Shirley + Linear:
To perform the Shirley + Linear Optimisation routine:
a) Have the file of interest open
b) From the upper window, click on Background
c) In the resulting box, change or optimise the Shirley + Linear
Slope as desired
•
Using Optimize in the Shirley + Linear window can cause problems. Adjust manually if necessary 3. Click on Accept when satisfied
Adding/Adjusting Peaks Note: The Background MUST be correct before peaks can be added. Nothing will happen otherwise. See previous section.
• To add a peak, from the Region Window, click on Add Peak
• The peak window appears
• This may be adjusted as below using the Peak Window which will
have opened automatically
In the XPS Peak Processing (lower) window, there will be a list of Regions , which are all the open files, and beside each of these will be numbers representing the synthetic peaks included in that region.
1. Click on a region number to activate that region
• The active region will be displayed in the upper window
2. Click on a peak number to start adjusting the parameters for that peak.
Regions
(files) Peaks
• The Processing window for that peak will open
3. Click off Fix to adjust the following using the maximum/minimum arrow
keys provided:
• Peak Type. (i.e. orbital – s, p, d, f)
• S.O.S (∆ eV between the two halves of the peak)
• Position
• FWHM
• Area
• %Lorenzian-Gaussian
• See the notes for explanations of how Asymmetry works.
4. Click on Accept when satisfied
Peak Types: p, d and f.
1. Each of these peaks combines the two splitting peaks
2. The FWHM is the same for both the splitting peaks, e.g. a p-type peak
with FWHM=0.7eV is the combination of a p3/2 with FWHM at 0.7eV and
a p1/2 with FWHM at 0.7eV, and with an area ratio of 2 to 1
3. If the theoretical area ratio is not true for the split peaks, the old way of
setting two s-type peaks and adding the constraints should be used. • The S.O.S. stands for spin orbital splitting.
Note: The FWHM of the p, d or f peaks are the FWHM of the p3/2,d5/2 or f7/2, respectively. The FWHM of the combined peaks (e.g. combination of p3/2 and p1/2) is shown in the actual FWHM in the Peak Parameter Window.
Peak Constraints
1. Each parameter can be referenced to the same type of parameter in
other peaks. For example, for four peaks (Peak #0, 1, 2 and 3) with known relative peak positions (0.5eV between adjacent peaks), the following can be used
• Position: Peak 1 = Peak 0 + 0.5eV
• Position: Peak 2 = Peak 1 + 0.5eV
• Position: Peak 3 = Peak 2 + 0.5eV
2. You may reference to any peak except with looped references.
3. The optimisation of the %GL value is allowed in this program.
• A suggestion to use this feature is to find a nice peak for a certain setting of your instrument and optimise the %GL for this peak.
• Fix the %GL in the later peak fitting process when the same instrument settings were used.
4. This version also includes the setting of the upper and lower bounds for
each parameter.
Peak Parameters
This program uses the following asymmetric Gaussian-Lorentzian sum
The program also uses the following symmetrical Gaussian-Lorentzian product function
Peak Function
Note:
If the selection is the sum function, when the user opens a *.xps file that was optimised using the Gaussian-Lorentzian product function, you have to re-optimise the spectra using the Gaussian-Lorentzian sum function with a different %Gaussian-Lorentzian value.
• You can choose the function type you want
1. From the lower window, click on the Options button
• The peak parameters box comes up
• Select GL sum for the Gaussian-Lorentzian sum function
• Select GL product for the Gaussian-Lorentzian product function.
2. For the Gaussian-Lorentzian sum function, each peak can have six
parameters
• Peak Position
• Area
• FWHM
• %Gaussian-Lorentzian
• TS
• TL
If anyone knows what TS or TL might be, please let me know. Thanks, CMH
3. Each peak in the Gaussian-Lorentzian product function can have four
parameters
• Peak Position
• Area
• FWHM
• %Gaussian-Lorentzian
Since peak area relates to the atomic concentration directly, we use it as a peak parameter and the peak height will not be shown to the user.
Note: F or asymmetric peaks, the FWHM only refers to the half of the peak that is symmetrical. The actual FWHM of the peak is calculated numerically and is shown after the actual FWHM in the Peak Parameter Window. If the asymmetric peak is a doublet (p, d or f type peak), the actual FWHM is the FWHM of the doublet.
Region Shift
A Region Shift parameter was added under the Parameters menu
• Use this parameter to compensate for the charging effect, the fermi level shift or any change in the system work function
• This value will be added to all the peak positions in the region for fitting purposes.
An example:
• A polymer surface is positively charged and all the peaks are shifted to the high binding energy by +0.5eV, e.g. aliphatic carbon at 285.0eV shifts to 285.5eV
• When the Region Shift parameter is set to +0.5eV, 0.5eV will be added to all the peak positions in the region during peak fitting, but the listed peak positions are not changed, e.g. 285.0eV for aliphatic carbon. Note: I have tried this without any actual shift taking place. If someone finds out how to perform this operation, please let me know. Thanks, CMH.
In the meantime, I suggest you do the shift before converting your files from the Vision Software format.
Optimisation
You can optimise:
1. A single peak parameter
• Use the Optimize button beside the parameter in the Peak Fitting window
2. The peak (the peak position, area, FWHM, and the %GL if the "fix" box is
not ticked)
• Use the Optimize Peak button at the base of the Peak Fitting window
3. A single region (all the parameters of all the peaks in that region if the
"fix" box is not ticked)
• Use the Optimize Region menu (button) in the upper window
4. All the regions
• Use the Optimize All button in the lower window
• During any type of optimisation, you can press the "Stop Fitting" button and the program will stop the process in the next cycle.
Print/Export
In the XPS Peak Fit or Region window, From the Data menu, choose Export or Print options as desired
Export
• The program can export the ASCII file of spectrum (*.DAT) for making high quality figures using other software (e.g. SigmaPlot)
• It can export the parameters (*.PAR) for further calculations (e.g. use Excel for atomic ratio calculations)
• It can also copy the spectral image to the system clipboard so that the spectral image can be pasted into a document (e.g. MS WORD). Program Options
1. The %tolerance allows the optimisation routine to stop if the change in
the difference after one loop is less that the %tolerance
2. The default setting of the optimisation is Newton's method
• This method requires a delta value for the optimisation calculations • You may need to change the value in some cases, but the existing setting is enough for most data.
3. For the binary search method, it searches the best fit for each parameter
in up to four levels of value ranges
• For example, for a peak position, in first level, it calculates the chi^2 when the peak position is changed by +2eV, +1.5eV, +1eV, +0.5eV,
-0.5eV, -1eV, -1.5eV, and -2eV (range 2eV, step 0.5eV) • Then, it selects the position value that gives the lowest chi^2
• In the second level, it searches the best values in the range +0.4eV, +0.3eV, +0.2eV, +0.1eV, -0.1eV, -0.2eV, -0.3eV, and -0.4eV (range
0.4eV, step 0.1eV)
• In the third level, it selects the best value in +0.09eV, +0.08eV, ...+0.01eV, -0.01eV, ...-0.09eV
• This will give the best value with two digits after decimal
• Level 4 is not used in the default setting
• The range setting and the number of levels in the option window can be changed if needed.
4. The Newton's Method or Binary Search Method can be selected by
clicking the "use" selection box of that method.
5. The selection of the peak function is also in the Options window.
6. The user can save/read the option parameters with the file extension
*.opa
• The program reads the default.opa file at start up. Therefore, the user can customize the program options by saving the selections
into the default.opa file.
Compatibility
The program can read:
• Kratos text (*.des) files together with the peak fitting parameters in the file
• The ASCII files exported from Phi's Multiplex software
• The ASCII files of Leybold's software
• The VAMAS file format
• For the Phi, Leybold and VAMAS formats, multiple regions can be read
• For the Phi format, if the description contains a comma ",", the program will give an error. (If you get the error, you may use any text
editor to remove the comma)
The program can also import ASCII files in the following format:
Binding Energy Value 1 Intensity Value 1
Binding Energy Value 2 Intensity Value 2
etc etc • The B.E. list must be in ascending or descending order, and the separation of adjacent B.E.s must be the same
• The file cannot have other lines before and after the data
• Sometimes, TAB may cause a reading error.
File I/O
The file format of XPSPEAK 4.1 is different from XPSPEAK 3.1, 3.0 and 2.0 • XPSPEAK 4.1 can read the file format of XPSPEAK 3.1, 3.0 and 2.0, but not the reverse
• File format of 4.1 is the same as that of 4.0.。