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	hartrees
Energy at 0K	-154.275744
Energy at 298.15K	-154.278572
HF Energy	-153.657215
Nuclear repulsion energy	97.465064

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)
1	A_g	3253	3159
2	A_g	1518	1474
3	A_g	1107	1075
4	A_g	934	907
5	A_u	695	675
6	A_u	472	459
7	B_1g	773	751
8	B_1u	3240	3147
9	B_1u	1546	1502
10	B_1u	1035	1005
11	B_2g	511	496
12	B_2u	3221	3129
13	B_2u	1249	1213
14	B_2u	711	690
15	B_3g	3207	3115
16	B_3g	1150	1117
17	B_3g	849	824
18	B_3u	551	536

Atom	y (Å)	z (Å)
C1	0.683	0.792
C2	0.683	-0.792
C3	-0.683	0.792
C4	-0.683	-0.792
H5	1.455	1.565
H6	1.455	-1.565
H7	-1.455	1.565
H8	-1.455	-1.565

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5833	1.3653	2.0906	1.0930	2.4797	2.2735	3.1817
C2	1.5833		2.0906	1.3653	2.4797	1.0930	3.1817	2.2735
C3	1.3653	2.0906		1.5833	2.2735	3.1817	1.0930	2.4797
C4	2.0906	1.3653	1.5833		3.1817	2.2735	2.4797	1.0930
H5	1.0930	2.4797	2.2735	3.1817		3.1291	2.9109	4.2737
H6	2.4797	1.0930	3.1817	2.2735	3.1291		4.2737	2.9109
H7	2.2735	3.1817	1.0930	2.4797	2.9109	4.2737		3.1291
H8	3.1817	2.2735	2.4797	1.0930	4.2737	2.9109	3.1291

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	135.003
C1	C3	C4	90.000	C1	C3	H7	134.997
C2	C1	C3	90.000	C2	C1	H5	135.003
C2	C4	C3	90.000	C3	C1	H5	134.997
C4	C2	H6	134.997	C4	C3	H7	135.003

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: CCSD(T)=FULL/aug-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(T)=FULL/aug-cc-pVDZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)