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	hartrees
Energy at 0K	-154.273549
Energy at 298.15K	-154.276412
HF Energy	-153.667932
Nuclear repulsion energy	98.515349

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3283	3109	0.00
2	A_g	1578	1494	0.00
3	A_g	1135	1075	0.00
4	A_g	979	928	0.00
5	A_u	725	686	0.00
6	A_u	481	456	0.00
7	B_1g	792	750	0.00
8	B_1u	3272	3099	19.30
9	B_1u	1586	1502	1.51
10	B_1u	1057	1001	1.41
11	B_2g	500	473	0.00
12	B_2u	3251	3079	10.83
13	B_2u	1269	1202	35.90
14	B_2u	741	702	7.47
15	B_3g	3237	3066	0.00
16	B_3g	1182	1120	0.00
17	B_3g	854	809	0.00
18	B_3u	551	522	152.70

Atom	y (Å)	z (Å)
C1	0.673	0.785
C2	0.673	-0.785
C3	-0.673	0.785
C4	-0.673	-0.785
H5	1.440	1.550
H6	1.440	-1.550
H7	-1.440	1.550
H8	-1.440	-1.550

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5706	1.3462	2.0686	1.0832	2.4579	2.2475	3.1495
C2	1.5706		2.0686	1.3462	2.4579	1.0832	3.1495	2.2475
C3	1.3462	2.0686		1.5706	2.2475	3.1495	1.0832	2.4579
C4	2.0686	1.3462	1.5706		3.1495	2.2475	2.4579	1.0832
H5	1.0832	2.4579	2.2475	3.1495		3.0995	2.8809	4.2316
H6	2.4579	1.0832	3.1495	2.2475	3.0995		4.2316	2.8809
H7	2.2475	3.1495	1.0832	2.4579	2.8809	4.2316		3.0995
H8	3.1495	2.2475	2.4579	1.0832	4.2316	2.8809	3.0995

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.891
C1	C3	C4	90.000	C1	C3	H7	135.109
C2	C1	C3	90.000	C2	C1	H5	134.891
C2	C4	C3	90.000	C3	C1	H5	135.109
C4	C2	H6	135.109	C4	C3	H7	134.891

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: MP2=FULL/6-311G*

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=FULL/6-311G*

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)