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	hartrees
Energy at 0K	-154.497612
Energy at 298.15K	-154.500700
HF Energy	-154.497612
Nuclear repulsion energy	98.704148

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3277	3150	0.00
2	A_g	1662	1598	0.00
3	A_g	1122	1079	0.00
4	A_g	964	927	0.00
5	A_u	890	856	0.00
6	A_u	537	517	0.00
7	B_1g	882	848	0.00
8	B_1u	3265	3139	16.92
9	B_1u	1670	1605	2.37
10	B_1u	1046	1006	0.53
11	B_2g	609	585	0.00
12	B_2u	3242	3117	7.61
13	B_2u	1256	1207	39.35
14	B_2u	738	709	9.62
15	B_3g	3225	3100	0.00
16	B_3g	1174	1128	0.00
17	B_3g	839	807	0.00
18	B_3u	594	571	115.65

Atom	y (Å)	z (Å)
C1	0.668	0.785
C2	0.668	-0.785
C3	-0.668	0.785
C4	-0.668	-0.785
H5	1.441	1.554
H6	1.441	-1.554
H7	-1.441	1.554
H8	-1.441	-1.554

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5705	1.3362	2.0620	1.0901	2.4638	2.2447	3.1497
C2	1.5705		2.0620	1.3362	2.4638	1.0901	3.1497	2.2447
C3	1.3362	2.0620		1.5705	2.2447	3.1497	1.0901	2.4638
C4	2.0620	1.3362	1.5705		3.1497	2.2447	2.4638	1.0901
H5	1.0901	2.4638	2.2447	3.1497		3.1085	2.8815	4.2387
H6	2.4638	1.0901	3.1497	2.2447	3.1085		4.2387	2.8815
H7	2.2447	3.1497	1.0901	2.4638	2.8815	4.2387		3.1085
H8	3.1497	2.2447	2.4638	1.0901	4.2387	2.8815	3.1085

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.865
C1	C3	C4	90.000	C1	C3	H7	135.135
C2	C1	C3	90.000	C2	C1	H5	134.865
C2	C4	C3	90.000	C3	C1	H5	135.135
C4	C2	H6	135.135	C4	C3	H7	134.865

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: PBE1PBE/cc-pVDZ

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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Number	Element	Mulliken
1	C	-0.006
2	C	-0.006
3	C	-0.006
4	C	-0.006
5	H	0.006
6	H	0.006
7	H	0.006
8	H	0.006

<r²>	57.837
(<r²>)^1/2	7.605

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: PBE1PBE/cc-pVDZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)