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	hartrees
Energy at 0K	-154.218574
Energy at 298.15K	-154.221602
HF Energy	-153.652974
Nuclear repulsion energy	97.764596

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3278	3145	0.00
2	A_g	1588	1524	0.00
3	A_g	1125	1079	0.00
4	A_g	954	915	0.00
5	A_u	816	783	0.00
6	A_u	518	497	0.00
7	B_1g	837	803	0.00
8	B_1u	3265	3133	18.57
9	B_1u	1612	1546	2.97
10	B_1u	1047	1005	0.08
11	B_2g	583	559	0.00
12	B_2u	3245	3114	8.82
13	B_2u	1276	1224	30.31
14	B_2u	739	709	8.46
15	B_3g	3231	3100	0.00
16	B_3g	1179	1132	0.00
17	B_3g	861	826	0.00
18	B_3u	590	566	109.04

Atom	y (Å)	z (Å)
C1	0.678	0.791
C2	0.678	-0.791
C3	-0.678	0.791
C4	-0.678	-0.791
H5	1.453	1.563
H6	1.453	-1.563
H7	-1.453	1.563
H8	-1.453	-1.563

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5820	1.3559	2.0836	1.0935	2.4780	2.2661	3.1749
C2	1.5820		2.0836	1.3559	2.4780	1.0935	3.1749	2.2661
C3	1.3559	2.0836		1.5820	2.2661	3.1749	1.0935	2.4780
C4	2.0836	1.3559	1.5820		3.1749	2.2661	2.4780	1.0935
H5	1.0935	2.4780	2.2661	3.1749		3.1254	2.9054	4.2673
H6	2.4780	1.0935	3.1749	2.2661	3.1254		4.2673	2.9054
H7	2.2661	3.1749	1.0935	2.4780	2.9054	4.2673		3.1254
H8	3.1749	2.2661	2.4780	1.0935	4.2673	2.9054	3.1254

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.886
C1	C3	C4	90.000	C1	C3	H7	135.114
C2	C1	C3	90.000	C2	C1	H5	134.886
C2	C4	C3	90.000	C3	C1	H5	135.114
C4	C2	H6	135.114	C4	C3	H7	134.886

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: QCISD/cc-pVDZ

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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All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: QCISD/cc-pVDZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)