First Observation of Defined Structural Motifs in the Sulfur-Iodine Thermochemical Cycle and Their Role in Hydrogen Production

Table 7

Comparison of the INS and unscaled calculated frequencies, cm⁻¹. Note: le—left edge; vw—very weak; sp—strong peak; bp—broad peak; re—right edge; h—hump; sh—shoulder; d—doublet; m—medium; w—weak.

Calculated				Observed INS at 20 K					Additional interpretations
3wI	∏	4wI	∏	S2	S6	S8	S10	S11
		625	𝜈5	620^bp
		559	𝜈26	542^re				540^le
			𝜈27	503^le
462	𝜈17	465	𝜈13	456^h	420^re	420^vw	450^re	450^bp
	𝜈18			429^sh
390	𝜈6	379	𝜈6	408^bp	389^le	388^le	370^le	373^bp
		377	𝜈14
343	𝜈19	362	𝜈28	380^sp		341^m		325^m
	𝜈20		𝜈29
					300^sp	309^sp	290^sp	300^sp	Optical modes due to specific positions and orientations of the H-bond
				235^sp
		201	𝜈15	211^vw	195^m	192^m		188^m
		189	𝜈30	179^sh	177^m	178^m		175^m
			𝜈31
		169	𝜈7		163^m		159^m	160^m
				163^d					H3O^+ vibrations
				154^d
150	𝜈21				144^vw			133^sh
	𝜈22
101	𝜈8			102^sp	126^sp	130^sp	118^sp	117^sp
					100^d	100^d			H3O^+ vibrations
					92^d	91^d
		88	𝜈32	80^sp	83^sp	81^m
			𝜈33
		59	𝜈17	65^sp	65^sp	62^m
				50^sp	50^sp	50^m			Not assigned