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	hartrees
Energy at 0K	-154.208879
Energy at 298.15K	-154.211878
HF Energy	-153.647481
Nuclear repulsion energy	98.786531

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3339	3131	0.00
2	A_g	1631	1530	0.00
3	A_g	1161	1089	0.00
4	A_g	988	926	0.00
5	A_u	766	718	0.00
6	A_u	502	470	0.00
7	B_1g	826	774	0.00
8	B_1u	3327	3120	23.09
9	B_1u	1662	1559	2.62
10	B_1u	1090	1022	0.03
11	B_2g	547	513	0.00
12	B_2u	3307	3101	12.91
13	B_2u	1319	1237	26.64
14	B_2u	766	719	6.38
15	B_3g	3295	3090	0.00
16	B_3g	1228	1151	0.00
17	B_3g	894	838	0.00
18	B_3u	589	552	114.59

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	1.438	1.542
H6	1.438	-1.542
H7	-1.438	1.542
H8	-1.438	-1.542

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5681	1.3419	2.0639	1.0784	2.4495	2.2409	3.1399
C2	1.5681		2.0639	1.3419	2.4495	1.0784	3.1399	2.2409
C3	1.3419	2.0639		1.5681	2.2409	3.1399	1.0784	2.4495
C4	2.0639	1.3419	1.5681		3.1399	2.2409	2.4495	1.0784
H5	1.0784	2.4495	2.2409	3.1399		3.0846	2.8756	4.2171
H6	2.4495	1.0784	3.1399	2.2409	3.0846		4.2171	2.8756
H7	2.2409	3.1399	1.0784	2.4495	2.8756	4.2171		3.0846
H8	3.1399	2.2409	2.4495	1.0784	4.2171	2.8756	3.0846

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.674
C1	C3	C4	90.000	C1	C3	H7	135.326
C2	C1	C3	90.000	C2	C1	H5	134.674
C2	C4	C3	90.000	C3	C1	H5	135.326
C4	C2	H6	135.326	C4	C3	H7	134.674

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)