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	hartrees
Energy at 0K	-24.361724
Energy at 298.15K	-24.364665
HF Energy	-24.038326
Nuclear repulsion energy	48.711915

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3252	3142	0.00
2	A_g	1492	1442	0.00
3	A_g	1104	1067	0.00
4	A_g	947	916	0.00
5	A_u	748	722	0.00
6	A_u	510	493	0.00
7	B_1g	806	779	0.00
8	B_1u	3231	3122	44.41
9	B_1u	1492	1441	5.88
10	B_1u	1050	1015	2.40
11	B_2g	566	547	0.00
12	B_2u	3206	3098	20.70
13	B_2u	1259	1216	26.99
14	B_2u	691	668	9.67
15	B_3g	3185	3078	0.00
16	B_3g	1187	1147	0.00
17	B_3g	880	850	0.00
18	B_3u	609	589	257.69

Atom	y (Å)	z (Å)
C1	0.701	0.811
C2	0.701	-0.811
C3	-0.701	0.811
C4	-0.701	-0.811
H5	1.478	1.584
H6	1.478	-1.584
H7	-1.478	1.584
H8	-1.478	-1.584

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.6216	1.4025	2.1439	1.0965	2.5181	2.3126	3.2384
C2	1.6216		2.1439	1.4025	2.5181	1.0965	3.2384	2.3126
C3	1.4025	2.1439		1.6216	2.3126	3.2384	1.0965	2.5181
C4	2.1439	1.4025	1.6216		3.2384	2.3126	2.5181	1.0965
H5	1.0965	2.5181	2.3126	3.2384		3.1690	2.9563	4.3338
H6	2.5181	1.0965	3.2384	2.3126	3.1690		4.3338	2.9563
H7	2.3126	3.2384	1.0965	2.5181	2.9563	4.3338		3.1690
H8	3.2384	2.3126	2.5181	1.0965	4.3338	2.9563	3.1690

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.882
C1	C3	C4	90.000	C1	C3	H7	135.118
C2	C1	C3	90.000	C2	C1	H5	134.882
C2	C4	C3	90.000	C3	C1	H5	135.118
C4	C2	H6	135.118	C4	C3	H7	134.882

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)