I am using line graph to interpret my XRD and FTIR data of different samples (after different treatments). What is the difference in using line graph and scatter graph? Which graph is most popular for FTIR and XRD data?
You are asking about Excel, right? Then you cannot use line chart. It works completely differently. Check the link below for details.
In fact, Excel is the worst choice for analysis of the spectral data. There are many programs specially designed for scientific purposes such as Origin, MagicPlot, Fityk etc.
Use Origin software. Its best for plotting graphs of different types for different analysis. And also you can obtain many types of parameters, which you cant using excel software. Also in Origin you can modify and handle the line thickness, scale, ticks, range, coloring etc.
for XRD and FTIR line graphs are more preferred as scatter graphs leads to ambiguity as similar symbols confuses the reader and also peaks cannot be clearly visible as in the case of line graphs.
Line plot is not the choice for your data. I will suggest also to use two opensource and very useful software. One is for quickplotting your data. Just copy and paste your series from the clipboard or batch pot your txt files. It's called https://sourceforge.net/projects/mjograph/files/mjograph/ the other one is scidavis. It's an opensource and free clone of origin https://sourceforge.net/projects/scidavis/. Keep in mind that if you do routinely that kind of analysis is a good practice to create scripts to automate your workflow. Not only because it will become fast but you will ensure repetability to your workflow avoiding "human" error. R is the environment to go.