Table 4. Comparison of the lattice vibrational frequencies (cm⁻¹) from ADP analysis, Γ-point simulation, DFT calculation, INS and Raman measurements.

DFT-D a	INS a	Raman b	Γ-point e	ADP_Nosph f
29.3	27	25	35.7	39.4
48.1	46	46	48.6, 49.8	44.6
57.9	53	54	56.6, 57.1	56.6
60.1	58	63
67.3	64	64	66.6
76.3	69
77.1	72	71	78.0
81.5	79	77	81.4, 83.1	76.5
86.5	85		86.7, 87.4	85.2
91.7	88	90
93.4	95	98	93.9
97.3	97		97.8, 98.6	97.5
100.1	103	107	104.2
109.3	112		111.5–118.4
119.6 c	117 c
113.5 c	122 c
122.9 c	138 c
124.4	145	139	125.8–139.2
128.9	148	151	149.3	145.5
130.9 c	150 c	159	154.0, 156.8
145.4 d	162 d	162	161.4
150.6 d	164 d		167.4, 168.8
148 d	173 d
165.7 c	177 c

Notes: (a) dispersion-corrected density functional theory (DFT-D) calculations and inelastic neutron scattering (INS) (Hunter et al., 2015 ▸). (b) Raman spectroscopy under ambient conditions (room tem­per­ature and 1 atm) (Dreger et al., 2014 ▸). (c) Deformational vibrations from CN₂ wagging and NO₂ twisting. (d) Deformational vibrations from NO₂ twisting. (e) Simulated Γ-point of the α-FOX-7 unit cell (this work). (f) Normal mode analysis of nonspherical ADPs and model rbeg+3b+1f (this work).