. 2020 Jul 9;32(15):6676–6684. doi: 10.1021/acs.chemmater.0c02150

Table 3. Irreducible Representations, Optical Activities, and Vibrational Frequencies for the Cs₂TeI₆ Experimental and Phonopy-Calculated Zone-Center (q = 0) Phonon Modes^a.

type	modes	irrep	optical activity	ν_DFT (cm^–1)	ν_expr. (cm^–1)
acoustic	1, 2, 3	T_1u	silent	0.00	n/a
optical	4, 5, 6	T_1g	silent	12.95	n/a
	7, 8, 9	T_2g	Raman	35.08	27.10 (12)
	10, 11	T_1u TO	IR	38.08	62.6 (1.3)^a
	12, 13, 14	T_2u	Silent	41.26	n/a
	15	T_1u LO	IR	45.99	94.6 (1.5)^a
	16, 17, 18	T_2g	Raman	59.12	55.46 (4)
	19, 20	T_1u TO	IR	61.46	155.19 (16)^a
	21	T_1u LO	IR	61.48	165.2 (5)^a
	22, 23	E_g	Raman	107.41	97.73 (3)
	24	A_1g	Raman	121.76	111.212 (13)
	25, 26	T_1u TO	IR	162.01	171 (2)
	27	T_1u LO	IR	178.73	175.6 (1.8)

See text for details.

Table 3. Irreducible Representations, Optical Activities, and Vibrational Frequencies for the Cs2TeI6 Experimental and Phonopy-Calculated Zone-Center (q = 0) Phonon Modesa.