How to get the amplitude vector, direction and angle of vectors of vibrational modes of atoms in IR spectra calculation in Materials-Studio-CASTEP ?
I am simulating crystal structures of tricalcium silicate, dicalcium silicate, etc. to obtain the IR spectra of the molecules using CASTEP. When I do the Anaylsis of the IR spectrum, I can see all the vibrational modes. I want to understand the bending/stretching modes in the MIR/FIR frequency region - such as symmetric/asymmetric or in-plane/out-of-plane.
But, I don't want to confirm the type of modes only from vizualization, I want to quantify the type of modes, from the change in bond angle, apmlitude of vector, etc. For this purpose, I want to know the amplitude, directions and angles of the vectors of the motions of the atoms. All these information, I am not being able to find in the CASTEP output file. I found a file .phonons which was hidden but in that file, for each corresponding vibrational mode at a particlular frequency, the intensity value is not matching with what I found in the CASTEP output file or in the IR spectra window where I see the vibrational modes. I am confused as to why is there a difference in the intensity values.
I would be obligded if I can get some help in this.