Density of states and Raman spectroscopy

[INARS]

Hello everyone

Lately I am taking some problem with my thesys, I am not an expert in theoretical physics but not bad as experimetal.
I want to calculate the contribution of the w(q) away from zone O ob Brillouin to fit my experimental data to the theory and to know if the quantum theory work in Raman spectroscopy. I have the diagram of density of states, but i have to take the different w(q) to calculate the intensity of Raman mode dependin how far it is from BZc and sum all of them to obtain the final Raman vibration shape and shift. My problem is I don't know hoe to take those w(q) form the diagram DOS and how they look. Could you help me on this

 

[eljose79]

Hello there! I am a theoretical physicist and I would be happy to assist you with your problem. The w(q) term you are referring to is the phonon dispersion relation, which is the relationship between the phonon frequency and its wave vector. This term is crucial in understanding the behavior of phonons in a crystal lattice, which in turn affects the Raman scattering intensity.

To obtain the w(q) values, you can use the density of states (DOS) diagram as a guide. The DOS diagram shows the number of states at each energy level, and the peaks in the diagram correspond to the phonon frequencies. The w(q) values can be calculated by taking the derivative of the DOS with respect to energy.

As for the contribution of w(q) away from the Brillouin zone, you can use the concept of zone folding. This means that the phonon dispersion relation repeats itself at multiples of the Brillouin zone, so you can use the w(q) values from the first Brillouin zone to calculate the contributions in other zones.

I hope this helps you with your calculations and understanding of the quantum theory in Raman spectroscopy. Let me know if you have any further questions. Good luck with your research!