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	hartrees
Energy at 0K	-154.342646
Energy at 298.15K
HF Energy	-153.689628
Nuclear repulsion energy	98.847520

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3297	3124	0.00
2	A_g	1599	1515	0.00
3	A_g	1137	1078	0.00
4	A_g	969	919	0.00
5	A_u	617	585	0.00
6	A_u	341i	323i	0.00
7	B_1g	783	742	0.00
8	B_1u	3285	3113	17.79
9	B_1u	1621	1536	5.71
10	B_1u	1071	1014	0.30
11	B_2g	467	442	0.00
12	B_2u	3265	3094	10.35
13	B_2u	1293	1225	31.80
14	B_2u	747	707	7.96
15	B_3g	3251	3081	0.00
16	B_3g	1206	1143	0.00
17	B_3g	873	828	0.00
18	B_3u	578	548	140.46

Atom	y (Å)	z (Å)
C1	0.669	0.785
C2	0.669	-0.785
C3	-0.669	0.785
C4	-0.669	-0.785
H5	1.436	1.543
H6	1.436	-1.543
H7	-1.436	1.543
H8	-1.436	-1.543

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5694	1.3388	2.0629	1.0785	2.4508	2.2381	3.1388
C2	1.5694		2.0629	1.3388	2.4508	1.0785	3.1388	2.2381
C3	1.3388	2.0629		1.5694	2.2381	3.1388	1.0785	2.4508
C4	2.0629	1.3388	1.5694		3.1388	2.2381	2.4508	1.0785
H5	1.0785	2.4508	2.2381	3.1388		3.0860	2.8725	4.2160
H6	2.4508	1.0785	3.1388	2.2381	3.0860		4.2160	2.8725
H7	2.2381	3.1388	1.0785	2.4508	2.8725	4.2160		3.0860
H8	3.1388	2.2381	2.4508	1.0785	4.2160	2.8725	3.0860

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.679
C1	C3	C4	90.000	C1	C3	H7	135.321
C2	C1	C3	90.000	C2	C1	H5	134.679
C2	C4	C3	90.000	C3	C1	H5	135.321
C4	C2	H6	135.321	C4	C3	H7	134.679

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: CCSD=FULL/TZVP

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=FULL/TZVP

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)