Subtract the background and Converting kinetic energy to binding energy

Hi, those are rather general questions, so it's a bit difficult to come up with an answer.

1) A graph is only a representation of data contained in a wave. I guess you want to subtract a background from your data (i.e. from a wave). Now, 'background' is an elastic term. Probably you want a background based on a physical model. So, what kind of background do you want to subtract actually, or do you have already some 'background data' prepared? If it is just an arbitrary background you want to get rid of, there may be a solution in the 'Baseline Spline Fit' package found in the projects section.

2) It depends: Is your data represented in the x vs y data format or do you have a x-scaling encoded in you wave (i.e. XY model or waveform model)? In the former case you obtain binding energy by subtracting a constant (i.e. the photon energy or your fermi reference) from your x data. In the latter case you subtract the same constant but this time from your scaling onset. Go to Data -> Change Wave Scaling... and choose 'Start and Delta' for the set scale mode. Then double-click your wave to load the current scaling into the fields. Adjust the start value and accept.

February 8, 2012 at 02:24 pm - Permalink