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	hartrees
Energy at 0K	-154.102333
Energy at 298.15K	-154.105462
HF Energy	-153.640721
Nuclear repulsion energy	99.274415

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3371	3114	0.00
2	A_g	1715	1584	0.00
3	A_g	1183	1093	0.00
4	A_g	1013	936	0.00
5	A_u	836	772	0.00
6	A_u	545	503	0.00
7	B_1g	880	813	0.00
8	B_1u	3360	3104	20.22
9	B_1u	1730	1598	2.51
10	B_1u	1113	1028	0.29
11	B_2g	597	552	0.00
12	B_2u	3338	3083	9.80
13	B_2u	1340	1238	33.88
14	B_2u	787	727	8.80
15	B_3g	3323	3070	0.00
16	B_3g	1240	1145	0.00
17	B_3g	895	826	0.00
18	B_3u	620	572	139.81

Atom	y (Å)	z (Å)
C1	0.664	0.782
C2	0.664	-0.782
C3	-0.664	0.782
C4	-0.664	-0.782
H5	1.433	1.539
H6	1.433	-1.539
H7	-1.433	1.539
H8	-1.433	-1.539

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5645	1.3289	2.0527	1.0785	2.4454	2.2295	3.1285
C2	1.5645		2.0527	1.3289	2.4454	1.0785	3.1285	2.2295
C3	1.3289	2.0527		1.5645	2.2295	3.1285	1.0785	2.4454
C4	2.0527	1.3289	1.5645		3.1285	2.2295	2.4454	1.0785
H5	1.0785	2.4454	2.2295	3.1285		3.0788	2.8651	4.2057
H6	2.4454	1.0785	3.1285	2.2295	3.0788		4.2057	2.8651
H7	2.2295	3.1285	1.0785	2.4454	2.8651	4.2057		3.0788
H8	3.1285	2.2295	2.4454	1.0785	4.2057	2.8651	3.0788

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: CID/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: CID/6-31G*

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)