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	hartrees
Energy at 0K	-152.600242
Energy at 298.15K	-152.603300
HF Energy	-152.600242
Nuclear repulsion energy	98.283310

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3564	3144	0.00
2	A_g	1790	1579	0.00
3	A_g	1253	1106	0.00
4	A_g	1054	929	0.00
5	A_u	938	827	0.00
6	A_u	573	506	0.00
7	B_1g	961	848	0.00
8	B_1u	3546	3128	2.12
9	B_1u	1807	1594	0.00
10	B_1u	1130	997	2.41
11	B_2g	691	610	0.00
12	B_2u	3510	3096	30.52
13	B_2u	1385	1222	35.72
14	B_2u	837	738	0.91
15	B_3g	3488	3077	0.00
16	B_3g	1265	1116	0.00
17	B_3g	938	827	0.00
18	B_3u	664	586	65.86

Atom	y (Å)	z (Å)
C1	0.669	0.792
C2	0.669	-0.792
C3	-0.669	0.792
C4	-0.669	-0.792
H5	1.455	1.553
H6	1.455	-1.553
H7	-1.455	1.553
H8	-1.455	-1.553

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5831	1.3372	2.0723	1.0945	2.4727	2.2560	3.1632
C2	1.5831		2.0723	1.3372	2.4727	1.0945	3.1632	2.2560
C3	1.3372	2.0723		1.5831	2.2560	3.1632	1.0945	2.4727
C4	2.0723	1.3372	1.5831		3.1632	2.2560	2.4727	1.0945
H5	1.0945	2.4727	2.2560	3.1632		3.1054	2.9101	4.2559
H6	2.4727	1.0945	3.1632	2.2560	3.1054		4.2559	2.9101
H7	2.2560	3.1632	1.0945	2.4727	2.9101	4.2559		3.1054
H8	3.1632	2.2560	2.4727	1.0945	4.2559	2.9101	3.1054

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.062
C1	C3	C4	90.000	C1	C3	H7	135.938
C2	C1	C3	90.000	C2	C1	H5	134.062
C2	C4	C3	90.000	C3	C1	H5	135.938
C4	C2	H6	135.938	C4	C3	H7	134.062

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: PBE1PBE/STO-3G

States and conformations

	Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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Number	Element	Mulliken
1	C	-0.086
2	C	-0.086
3	C	-0.086
4	C	-0.086
5	H	0.086
6	H	0.086
7	H	0.086
8	H	0.086

<r²>	57.160
(<r²>)^1/2	7.560

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: PBE1PBE/STO-3G

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)