Polarized Raman Spectra of NH_𝟒Al(SO_𝟒)_𝟐⋅𝟏𝟐H_𝟐O

Table 1

Active modes of NH₄Al(SO₄)₂⋅12H₂O.

	External modes							Internal modes
	LSO4,TSO4,TAl,,LH2O,TH2O,LNH4,TNH4							SO4				NH4				H2O			Activity
								𝜈1	𝜈2	𝜈3	𝜈4	𝜈1	𝜈2	𝜈3	𝜈4	𝜈1	𝜈2	𝜈3	Raman
Ag	1	1	0	3	3	1	1	1	0	1	1	1	0	1	1	2	2	2	(𝛼𝑥𝑥+𝛼𝑦𝑦+𝛼𝑧𝑧)
Eg	1	1	0	3	3	1	1	0	1	1	1	0	1	1	1	2	2	2	(2𝛼𝑧𝑧0𝑥02012𝛼𝑥𝑥−𝛼𝑦𝑦,𝛼𝑥𝑥0𝑥02012𝛼𝑦𝑦)
Fg	3	3	0	9	9	3	3	1	2	3	3	1	2	3	3	2	2	2	(𝛼𝑥𝑦,𝛼𝑦𝑧,𝛼𝑥𝑧)