Fukui Function Analysis and Optical, Electronic, and Vibrational Properties of Tetrahydrofuran and Its Derivatives: A Complete Quantum Chemical Study

Table 2

Vibrational assignments of tetrahydrofuran (modes having high IR intensity only) with B3LYP/6-311 G (d, p).

B3LYP (calculated) unscaled	B3LYP (calculated) scaled (in lit.)	IR (int.)	Exp. IR	Exp. Raman	Vibrational assignments
281	271 (267)	8.1672	—	276	Out of plane bend in CH2–O–CH2
644	620 (635)	4.7345	625	—	(C–O–C–C)
799	769	5.8498	765	—	Twist CH2
866	834	4.358	825	—	Twist CH2 in whole
901	868 (883)	5.7608	865	—	(C–C–C–O)
941	906	22.7829	915	913	Twist CH2 in whole
959	924 (934)	17.9192	930	—	Ring breathing
1046	1007	4.7743	995	—	(C–C–H) + (C–O–C)
1097	1056 (1068)	83.1142	1045	1071	Ring deformation
1214	1169	6.4279	1175	1174	(C–C–H)
1261	1214 (1214)	5.8725	1205	—	Twist CH2
1268	1221	5.1994	1220	1234	Twist CH2
1395	1343	4.7295	1335	1335	(C–C–H)
1506	1450 (1454)	5.5918	1445	1452	S(CH2)
2958	2848	43.4017	2840	—	(C–H)
2964	2854	118.3793	2855	—	(C–H)
3052	2939 (2936)	24.963	2930	2938	(C–H)
3062	2949	40.015	2950	—	(C–H)
3082	2968 (2968)	19.4174	2965	2975	(C–H)
3098	2983 (2989)	34.7534	2980	—	(C–H)
3110	2995	77.426	2990	—	(C–H)