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	hartrees
Energy at 0K	-154.487954
Energy at 298.15K	-154.491020
HF Energy	-153.706103
Nuclear repulsion energy	99.240688

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3300	3158	0.00
2	A_g	1586	1518	0.00
3	A_g	1130	1081	0.00
4	A_g	974	932	0.00
5	A_u	865	828	0.00
6	A_u	530	507	0.00
7	B_1g	875	838	0.00
8	B_1u	3290	3149	10.71
9	B_1u	1596	1528	3.25
10	B_1u	1061	1016	0.33
11	B_2g	590	565	0.00
12	B_2u	3269	3129	5.39
13	B_2u	1271	1216	34.73
14	B_2u	733	701	8.51
15	B_3g	3256	3116	0.00
16	B_3g	1203	1152	0.00
17	B_3g	857	820	0.00
18	B_3u	580	555	127.05

Atom	y (Å)	z (Å)
C1	0.668	0.780
C2	0.668	-0.780
C3	-0.668	0.780
C4	-0.668	-0.780
H5	1.427	1.541
H6	1.427	-1.541
H7	-1.427	1.541
H8	-1.427	-1.541

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5603	1.3356	2.0538	1.0749	2.4422	2.2287	3.1267
C2	1.5603		2.0538	1.3356	2.4422	1.0749	3.1267	2.2287
C3	1.3356	2.0538		1.5603	2.2287	3.1267	1.0749	2.4422
C4	2.0538	1.3356	1.5603		3.1267	2.2287	2.4422	1.0749
H5	1.0749	2.4422	2.2287	3.1267		3.0822	2.8539	4.2006
H6	2.4422	1.0749	3.1267	2.2287	3.0822		4.2006	2.8539
H7	2.2287	3.1267	1.0749	2.4422	2.8539	4.2006		3.0822
H8	3.1267	2.2287	2.4422	1.0749	4.2006	2.8539	3.0822

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	135.067
C1	C3	C4	90.000	C1	C3	H7	134.933
C2	C1	C3	90.000	C2	C1	H5	135.067
C2	C4	C3	90.000	C3	C1	H5	134.933
C4	C2	H6	134.933	C4	C3	H7	135.067

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: MP2=FULL/cc-pVQZ

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/cc-pVQZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)