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	hartrees
Energy at 0K	-154.356224
Energy at 298.15K	-154.359326
HF Energy	-153.695609
Nuclear repulsion energy	98.813622

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3282	3136	0.00
2	A_g	1600	1529	0.00
3	A_g	1135	1084	0.00
4	A_g	967	924	0.00
5	A_u	858	819	0.00
6	A_u	536	512	0.00
7	B_1g	872	833	0.00
8	B_1u	3270	3125	15.23
9	B_1u	1620	1548	4.02
10	B_1u	1068	1021	0.10
11	B_2g	601	574	0.00
12	B_2u	3249	3105	8.53
13	B_2u	1290	1233	33.47
14	B_2u	743	710	9.60
15	B_3g	3235	3091	0.00
16	B_3g	1205	1152	0.00
17	B_3g	870	831	0.00
18	B_3u	601	574	124.99

Atom	y (Å)	z (Å)
C1	0.670	0.785
C2	0.670	-0.785
C3	-0.670	0.785
C4	-0.670	-0.785
H5	1.433	1.546
H6	1.433	-1.546
H7	-1.433	1.546
H8	-1.433	-1.546

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5707	1.3391	2.0641	1.0779	2.4533	2.2362	3.1396
C2	1.5707		2.0641	1.3391	2.4533	1.0779	3.1396	2.2362
C3	1.3391	2.0641		1.5707	2.2362	3.1396	1.0779	2.4533
C4	2.0641	1.3391	1.5707		3.1396	2.2362	2.4533	1.0779
H5	1.0779	2.4533	2.2362	3.1396		3.0919	2.8667	4.2164
H6	2.4533	1.0779	3.1396	2.2362	3.0919		4.2164	2.8667
H7	2.2362	3.1396	1.0779	2.4533	2.8667	4.2164		3.0919
H8	3.1396	2.2362	2.4533	1.0779	4.2164	2.8667	3.0919

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.880
C1	C3	C4	90.000	C1	C3	H7	135.120
C2	C1	C3	90.000	C2	C1	H5	134.880
C2	C4	C3	90.000	C3	C1	H5	135.120
C4	C2	H6	135.120	C4	C3	H7	134.880

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: QCISD/cc-pVTZ

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: QCISD/cc-pVTZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)