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	hartrees
Energy at 0K	-154.388972
Energy at 298.15K	-154.392059
HF Energy	-153.696014
Nuclear repulsion energy	99.159142

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3311	3143	0.00
2	A_g	1587	1507	0.00
3	A_g	1136	1078	0.00
4	A_g	980	930	0.00
5	A_u	866	822	0.00
6	A_u	531	504	0.00
7	B_1g	873	828	0.00
8	B_1u	3298	3131	12.22
9	B_1u	1596	1515	2.58
10	B_1u	1067	1013	0.40
11	B_2g	597	567	0.00
12	B_2u	3272	3107	5.86
13	B_2u	1276	1212	34.32
14	B_2u	734	697	8.05
15	B_3g	3256	3091	0.00
16	B_3g	1211	1149	0.00
17	B_3g	858	815	0.00
18	B_3u	591	561	126.55

Atom	y (Å)	z (Å)
C1	0.669	0.781
C2	0.669	-0.781
C3	-0.669	0.781
C4	-0.669	-0.781
H5	1.428	1.540
H6	1.428	-1.540
H7	-1.428	1.540
H8	-1.428	-1.540

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5624	1.3374	2.0566	1.0732	2.4422	2.2294	3.1277
C2	1.5624		2.0566	1.3374	2.4422	1.0732	3.1277	2.2294
C3	1.3374	2.0566		1.5624	2.2294	3.1277	1.0732	2.4422
C4	2.0566	1.3374	1.5624		3.1277	2.2294	2.4422	1.0732
H5	1.0732	2.4422	2.2294	3.1277		3.0803	2.8550	4.1999
H6	2.4422	1.0732	3.1277	2.2294	3.0803		4.1999	2.8550
H7	2.2294	3.1277	1.0732	2.4422	2.8550	4.1999		3.0803
H8	3.1277	2.2294	2.4422	1.0732	4.1999	2.8550	3.0803

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	135.005
C1	C3	C4	90.000	C1	C3	H7	134.995
C2	C1	C3	90.000	C2	C1	H5	135.005
C2	C4	C3	90.000	C3	C1	H5	134.995
C4	C2	H6	134.995	C4	C3	H7	135.005

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: MP2=FULL/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: MP2=FULL/cc-pVTZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)