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	hartrees
Energy at 0K	-24.587807
Energy at 298.15K	-24.590808
HF Energy	-24.111416
Nuclear repulsion energy	49.506718

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3278	3112	0.00
2	A_g	1565	1486	0.00
3	A_g	1134	1077	0.00
4	A_g	977	928	0.00
5	A_u	811	770	0.00
6	A_u	514	488	0.00
7	B_1g	834	792	0.00
8	B_1u	3264	3099	20.54
9	B_1u	1578	1498	3.82
10	B_1u	1053	1000	2.03
11	B_2g	575	546	0.00
12	B_2u	3240	3076	8.56
13	B_2u	1266	1202	31.49
14	B_2u	756	718	10.52
15	B_3g	3222	3059	0.00
16	B_3g	1177	1118	0.00
17	B_3g	850	807	0.00
18	B_3u	602	572	228.25

Atom	y (Å)	z (Å)
C1	0.688	0.793
C2	0.688	-0.793
C3	-0.688	0.793
C4	-0.688	-0.793
H5	1.463	1.564
H6	1.463	-1.564
H7	-1.463	1.564
H8	-1.463	-1.564

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5858	1.3764	2.0998	1.0934	2.4813	2.2854	3.1913
C2	1.5858		2.0998	1.3764	2.4813	1.0934	3.1913	2.2854
C3	1.3764	2.0998		1.5858	2.2854	3.1913	1.0934	2.4813
C4	2.0998	1.3764	1.5858		3.1913	2.2854	2.4813	1.0934
H5	1.0934	2.4813	2.2854	3.1913		3.1286	2.9261	4.2837
H6	2.4813	1.0934	3.1913	2.2854	3.1286		4.2837	2.9261
H7	2.2854	3.1913	1.0934	2.4813	2.9261	4.2837		3.1286
H8	3.1913	2.2854	2.4813	1.0934	4.2837	2.9261	3.1286

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.871
C1	C3	C4	90.000	C1	C3	H7	135.129
C2	C1	C3	90.000	C2	C1	H5	134.871
C2	C4	C3	90.000	C3	C1	H5	135.129
C4	C2	H6	135.129	C4	C3	H7	134.871

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: MP2/CEP-31G*

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: MP2/CEP-31G*

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)