The straightforward way from my point of view would be to measure the empty cell and to subtract that as a background; is there anything that speaks against that?

Syed Furqan Ul Hassan Naqvi

I agree totally with Jürgen Weippert

Take a blank measurement in the closest way that replicates your actual experiment.

Jürgen Weippert Alan F Rawle Thank you for your answers.

I am unfamiliar with this approach. Some guidance will be helpful. Moreover, would this approach be correct if the unwanted peaks overlap the original peaks.

Syed Furqan Ul Hassan Naqvi

Not sure where your difficulty is. Perform the experiment without a sample, recording the spectrum. Then perform the experiment with sample. There should always be more signal with sample present than if no sample is present. Subtract one spectrum from another - many Raman software packages will do this for you if both records are stored. There will always be peak overlap but increased signal will subtract out the diamond peak. Only issue is that the energy delivered to the diamond may be less with sample present (i.e. the background gets over-subtracted) but this should be to your advantage. Ask anyone who does UV-VIS spectrometry with a double-beam instrument.

Alan F Rawle This has given me a very clear understanding. Now I hope the problem will be solved. I thank you for your answer.

One way to avoid the diamond peak is to do two separate measurements; one at 0cm-1 to about 1275cm-1 range, another range can start from about 1400cm-1 . Of course, this strategy will not work if you are expecting to see a peak very near the diamond peak.

Unfortunnatly, you can not I get rid of this peak. The Raman spectra of Diamond is very strong, and exciting volume is big. Moreover the suggestd above measurment emoty cell is hard to reproduce because for the best result you should mesure at exactly presure that pracicaly impossible.

In attached picture the dependence of spectra from pressure. As you can see the diamond line has a several components, because some line came from diamons surface inside cell where some pressure bur other component from outside cell where no extra pressure at all.

The Raman line position of the diamond anvil relative to its initial position (1332 cm−1) near the surface of the sample versus hydrostatic pressures. The circles, stars, and triangles correspond to the positions of different components of the Raman spectrum in the diamond anvil. The straight lines are linear fits of the pressure dependence for these frequency edges. The inset demonstrates the Raman line in the diamond anvil under the applied pressure of

6 GPa. The solid line is the fit of the experimental spectrum by a sum of three Lorentzians, and short dotted lines are the Lorentzian contours.