First-principles investigation of the Raman spectroscopy of perovskite-like crystal K3B6O10Cl

K3B6O10Cl is a newly synthesized perovskite-like non-linear optical crystal, which exhibits a large second harmonic generation response and deep UV absorption edge. We find 31 infrared active modes (12A1 + 19E) in it, although only ten peaks were observed in experiment. Based on the density-functional theory, we calculate the vibrational frequencies of K3B6O10Cl and classify them according to the internal and external modes of B6O10 and KCl6 groups. We further investigate the direction dispersion and find large LO-TO splitting in it. The calculated Raman spectra for different geometry configuration are depicted in detail. Our calculation results provide extraordinary insights into the Raman spectroscopy of this non-linear optical material.