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	hartrees
Energy at 0K	-153.589985
Energy at 298.15K	-153.593395
HF Energy	-153.589985
Nuclear repulsion energy	98.747775

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3489	3140	0.00
2	A_g	1732	1558	0.00
3	A_g	1215	1094	0.00
4	A_g	1037	933	0.00
5	A_u	1022	920	0.00
6	A_u	602	542	0.00
7	B_1g	1022	920	0.00
8	B_1u	3472	3125	25.45
9	B_1u	1739	1565	13.52
10	B_1u	1161	1045	2.92
11	B_2g	760	684	0.00
12	B_2u	3448	3103	7.34
13	B_2u	1396	1256	39.53
14	B_2u	782	704	16.79
15	B_3g	3432	3088	0.00
16	B_3g	1312	1181	0.00
17	B_3g	976	878	0.00
18	B_3u	719	647	261.82

Atom	y (Å)	z (Å)
C1	0.670	0.790
C2	0.670	-0.790
C3	-0.670	0.790
C4	-0.670	-0.790
H5	1.429	1.541
H6	1.429	-1.541
H7	-1.429	1.541
H8	-1.429	-1.541

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5798	1.3391	2.0710	1.0683	2.4515	2.2291	3.1365
C2	1.5798		2.0710	1.3391	2.4515	1.0683	3.1365	2.2291
C3	1.3391	2.0710		1.5798	2.2291	3.1365	1.0683	2.4515
C4	2.0710	1.3391	1.5798		3.1365	2.2291	2.4515	1.0683
H5	1.0683	2.4515	2.2291	3.1365		3.0819	2.8585	4.2035
H6	2.4515	1.0683	3.1365	2.2291	3.0819		4.2035	2.8585
H7	2.2291	3.1365	1.0683	2.4515	2.8585	4.2035		3.0819
H8	3.1365	2.2291	2.4515	1.0683	4.2035	2.8585	3.0819

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.670
C1	C3	C4	90.000	C1	C3	H7	135.330
C2	C1	C3	90.000	C2	C1	H5	134.670
C2	C4	C3	90.000	C3	C1	H5	135.330
C4	C2	H6	135.330	C4	C3	H7	134.670

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: HF/LANL2DZ

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	-0.229
2	C	-0.229
3	C	-0.229
4	C	-0.229
5	H	0.229
6	H	0.229
7	H	0.229
8	H	0.229

<r²>	58.277
(<r²>)^1/2	7.634

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: HF/LANL2DZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)