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	hartrees
Energy at 0K	-154.175791
Energy at 298.15K	-154.178729
HF Energy	-153.639146
Nuclear repulsion energy	98.651495

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3290	3114	0.00
2	A_g	1626	1539	0.00
3	A_g	1153	1091	0.00
4	A_g	983	930	0.00
5	A_u	737	698	0.00
6	A_u	502	475	0.00
7	B_1g	798	756	0.00
8	B_1u	3279	3104	21.91
9	B_1u	1653	1564	1.77
10	B_1u	1079	1021	0.42
11	B_2g	527	499	0.00
12	B_2u	3259	3085	12.05
13	B_2u	1301	1232	29.32
14	B_2u	763	722	7.05
15	B_3g	3246	3073	0.00
16	B_3g	1207	1143	0.00
17	B_3g	895	847	0.00
18	B_3u	579	548	126.13

Atom	y (Å)	z (Å)
C1	0.671	0.784
C2	0.671	-0.784
C3	-0.671	0.784
C4	-0.671	-0.784
H5	1.444	1.546
H6	1.444	-1.546
H7	-1.444	1.546
H8	-1.444	-1.546

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5689	1.3421	2.0646	1.0849	2.4553	2.2477	3.1470
C2	1.5689		2.0646	1.3421	2.4553	1.0849	3.1470	2.2477
C3	1.3421	2.0646		1.5689	2.2477	3.1470	1.0849	2.4553
C4	2.0646	1.3421	1.5689		3.1470	2.2477	2.4553	1.0849
H5	1.0849	2.4553	2.2477	3.1470		3.0922	2.8873	4.2306
H6	2.4553	1.0849	3.1470	2.2477	3.0922		4.2306	2.8873
H7	2.2477	3.1470	1.0849	2.4553	2.8873	4.2306		3.0922
H8	3.1470	2.2477	2.4553	1.0849	4.2306	2.8873	3.0922

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.589
C1	C3	C4	90.000	C1	C3	H7	135.411
C2	C1	C3	90.000	C2	C1	H5	134.589
C2	C4	C3	90.000	C3	C1	H5	135.411
C4	C2	H6	135.411	C4	C3	H7	134.589

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: CCD/6-31G*

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: CCD/6-31G*

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)