Negative sign for positive value x scale

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Tue, 07/15/2014 - 07:21 am

Dear All,
In the photoelectron spectroscopy studies, we always measure spectra in energy vs intensity. So, the loaded x-scale is by default positive number. But for presentation, we have to show as negative number. For the same, I have to put negative sign in front of the x-scale number. It is also possible to multiply with -1 to get the same, but for analysis process positive number is easy. I presently use drawing text tool to get "-" sign. This works good as long as I unchanged the size of the graph. When size is changed position of the text moves, I have even try to use coordinate system option like absolute, relative and plot relative.
So, I would like to know is there any option to give just "-" sign in-front of the x-scale value?
Something like "Units in Every tick Label", so that one can give "-" sign.
I thank you in advance for your help.
Regards,
Maniraj
Macro DemoGraphNegForPos()

    Make/O/N=20 data=p
    SetScale/I x, 100, 900, "", data
   
    Duplicate/O data, negativeXVals
    negativeXVals = -pnt2x(data,p)
   
    Display data vs negativeXVals
    SetAxis/A/R bottom
   
    // compare it to graphing just the waveform
    Display data
End


[Edit: actually chozo's solution below is better --Jim]

--Jim Prouty
Software Engineer, WaveMetrics, Inc.

July 15, 2014 at 12:26 pm - Permalink

mslv86 wrote:
Dear All,
In the photoelectron spectroscopy studies, we always measure spectra in energy vs intensity.


Just curious. As far as I know, and certainly in the US, photoelectron spectroscopy is shown as intensity versus binding energy, where binding energy runs in reverse (highest to lowest). Some times I do run across graphs of photoelectron spectra plotted with binding energy running from low to high. This seems always to happen in European-related publications.

I have NEVER seen photoelectron spectra presented with an energy scale that has negative signs. So, can you cite a reference for me to see what you mean.

Also, in case you are interested, SetAxis/A/R will reverse the axis scaling from typical low to high to the reverse high to low.

--
J. J. Weimer
Chemistry / Chemical & Materials Engineering, UAHuntsville

July 15, 2014 at 07:10 pm - Permalink

I also constantly run into this problem. I like to have my binding energy negative in the data, which is also one easy way to discern/recalculate to spectra with kinetic energy (positive, because that's for sure). The most simple way to just exchange the sign of the x axis for the graphical representation of your data is:
ModifyGraph muloffset={-1,0}
SetAxis/A/R bottom

July 15, 2014 at 07:40 pm - Permalink

chozo wrote:
The most simple way to just exchange the sign of the x axis for the graphical representation of your data is:
ModifyGraph muloffset={-1,0}
SetAxis/A/R bottom


chozo is the winner for best solution!

--Jim Prouty
Software Engineer, WaveMetrics, Inc.

July 16, 2014 at 09:50 pm - Permalink

Firstly, I thank you all for interest and solution.

jjweimer: You are right, in all the publication which only contains photoemission data, binding energy scale is shown in positive number. Since, it is binding energy one suppose to scale from high to low (in the sense that the Fermi edge position is at your right hand side), but some publication show it in low to high. But, as far as I know, the core photoemission group always show high to low.

Since, I am working with photoemission, inverse photoemission and two photon photoemission spectroscopy, I have to show photoemission spectra in negative scale to make it clear that it is binding energy.

chozo: I thank you again for most simplest solution, which give full degree of freedom to change the scale at any time.

July 17, 2014 at 03:35 am - Permalink