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	hartrees
Energy at 0K	-154.217680
Energy at 298.15K	-154.220714
HF Energy	-153.653098
Nuclear repulsion energy	97.794439

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3280	3107	0.00
2	A_g	1593	1509	0.00
3	A_g	1127	1067	0.00
4	A_g	955	905	0.00
5	A_u	818	775	0.00
6	A_u	519	491	0.00
7	B_1g	839	794	0.00
8	B_1u	3267	3095	18.09
9	B_1u	1616	1531	2.93
10	B_1u	1048	993	0.08
11	B_2g	584	553	0.00
12	B_2u	3248	3076	9.27
13	B_2u	1277	1210	30.20
14	B_2u	740	701	8.40
15	B_3g	3234	3063	0.00
16	B_3g	1181	1119	0.00
17	B_3g	865	820	0.00
18	B_3u	591	560	109.32

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	1.452	1.562
H6	1.452	-1.562
H7	-1.452	1.562
H8	-1.452	-1.562

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5817	1.3552	2.0829	1.0934	2.4775	2.2654	3.1741
C2	1.5817		2.0829	1.3552	2.4775	1.0934	3.1741	2.2654
C3	1.3552	2.0829		1.5817	2.2654	3.1741	1.0934	2.4775
C4	2.0829	1.3552	1.5817		3.1741	2.2654	2.4775	1.0934
H5	1.0934	2.4775	2.2654	3.1741		3.1249	2.9046	4.2663
H6	2.4775	1.0934	3.1741	2.2654	3.1249		4.2663	2.9046
H7	2.2654	3.1741	1.0934	2.4775	2.9046	4.2663		3.1249
H8	3.1741	2.2654	2.4775	1.0934	4.2663	2.9046	3.1249

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.885
C1	C3	C4	90.000	C1	C3	H7	135.115
C2	C1	C3	90.000	C2	C1	H5	134.885
C2	C4	C3	90.000	C3	C1	H5	135.115
C4	C2	H6	135.115	C4	C3	H7	134.885

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: CCSD/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: CCSD/cc-pVDZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)