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	hartrees
Energy at 0K	-154.257859
Energy at 298.15K	-154.260882
HF Energy	-153.676656
Nuclear repulsion energy	98.478376

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3282	3135	0.00
2	A_g	1606	1534	0.00
3	A_g	1136	1085	0.00
4	A_g	971	927	0.00
5	A_u	791	756	0.00
6	A_u	501	478	0.00
7	B_1g	847	809	0.00
8	B_1u	3270	3123	19.85
9	B_1u	1628	1554	3.23
10	B_1u	1062	1014	0.09
11	B_2g	566	540	0.00
12	B_2u	3249	3103	11.08
13	B_2u	1283	1226	30.61
14	B_2u	754	720	7.90
15	B_3g	3236	3091	0.00
16	B_3g	1196	1142	0.00
17	B_3g	883	843	0.00
18	B_3u	591	565	130.31

Atom	y (Å)	z (Å)
C1	0.672	0.788
C2	0.672	-0.788
C3	-0.672	0.788
C4	-0.672	-0.788
H5	1.441	1.550
H6	1.441	-1.550
H7	-1.441	1.550
H8	-1.441	-1.550

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5757	1.3432	2.0705	1.0831	2.4614	2.2458	3.1511
C2	1.5757		2.0705	1.3432	2.4614	1.0831	3.1511	2.2458
C3	1.3432	2.0705		1.5757	2.2458	3.1511	1.0831	2.4614
C4	2.0705	1.3432	1.5757		3.1511	2.2458	2.4614	1.0831
H5	1.0831	2.4614	2.2458	3.1511		3.1005	2.8817	4.2329
H6	2.4614	1.0831	3.1511	2.2458	3.1005		4.2329	2.8817
H7	2.2458	3.1511	1.0831	2.4614	2.8817	4.2329		3.1005
H8	3.1511	2.2458	2.4614	1.0831	4.2329	2.8817	3.1005

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.744
C1	C3	C4	90.000	C1	C3	H7	135.256
C2	C1	C3	90.000	C2	C1	H5	134.744
C2	C4	C3	90.000	C3	C1	H5	135.256
C4	C2	H6	135.256	C4	C3	H7	134.744

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: CCD/6-311G**

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: CCD/6-311G**

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)