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	hartrees
Energy at 0K	-153.707276
Energy at 298.15K	-153.710653
HF Energy	-153.707276
Nuclear repulsion energy	99.927329

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3401	3089	0.00
2	A_g	1750	1589	0.00
3	A_g	1207	1097	0.00
4	A_g	1025	931	0.00
5	A_u	1014	921	0.00
6	A_u	600	545	0.00
7	B_1g	1011	918	0.00
8	B_1u	3390	3080	14.37
9	B_1u	1772	1609	10.97
10	B_1u	1150	1045	0.03
11	B_2g	704	639	0.00
12	B_2u	3368	3059	9.63
13	B_2u	1395	1267	41.79
14	B_2u	802	729	14.76
15	B_3g	3352	3045	0.00
16	B_3g	1300	1181	0.00
17	B_3g	924	839	0.00
18	B_3u	676	614	165.27

Atom	y (Å)	z (Å)
C1	0.657	0.781
C2	0.657	-0.781
C3	-0.657	0.781
C4	-0.657	-0.781
H5	1.415	1.536
H6	1.415	-1.536
H7	-1.415	1.536
H8	-1.415	-1.536

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5624	1.3146	2.0419	1.0695	2.4381	2.2054	3.1087
C2	1.5624		2.0419	1.3146	2.4381	1.0695	3.1087	2.2054
C3	1.3146	2.0419		1.5624	2.2054	3.1087	1.0695	2.4381
C4	2.0419	1.3146	1.5624		3.1087	2.2054	2.4381	1.0695
H5	1.0695	2.4381	2.2054	3.1087		3.0725	2.8296	4.1770
H6	2.4381	1.0695	3.1087	2.2054	3.0725		4.1770	2.8296
H7	2.2054	3.1087	1.0695	2.4381	2.8296	4.1770		3.0725
H8	3.1087	2.2054	2.4381	1.0695	4.1770	2.8296	3.0725

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.908
C1	C3	C4	90.000	C1	C3	H7	135.092
C2	C1	C3	90.000	C2	C1	H5	134.908
C2	C4	C3	90.000	C3	C1	H5	135.092
C4	C2	H6	135.092	C4	C3	H7	134.908

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: HF/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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Number	Element	Mulliken
1	C	-0.150
2	C	-0.150
3	C	-0.150
4	C	-0.150
5	H	0.150
6	H	0.150
7	H	0.150
8	H	0.150

<r²>	57.115
(<r²>)^1/2	7.557

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: HF/cc-pVQZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)