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	hartrees
Energy at 0K	-154.197924
Energy at 298.15K	-154.200851
HF Energy	-153.647313
Nuclear repulsion energy	98.853516

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3344	3125	0.00
2	A_g	1607	1502	0.00
3	A_g	1157	1081	0.00
4	A_g	996	930	0.00
5	A_u	750	701	0.00
6	A_u	481	449	0.00
7	B_1g	813	760	0.00
8	B_1u	3333	3114	19.88
9	B_1u	1625	1518	1.97
10	B_1u	1088	1016	0.26
11	B_2g	522	488	0.00
12	B_2u	3313	3095	9.13
13	B_2u	1306	1220	29.19
14	B_2u	754	704	5.40
15	B_3g	3299	3082	0.00
16	B_3g	1219	1139	0.00
17	B_3g	859	803	0.00
18	B_3u	569	532	119.37

Atom	y (Å)	z (Å)
C1	0.672	0.782
C2	0.672	-0.782
C3	-0.672	0.782
C4	-0.672	-0.782
H5	1.437	1.541
H6	1.437	-1.541
H7	-1.437	1.541
H8	-1.437	-1.541

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5639	1.3435	2.0618	1.0779	2.4457	2.2413	3.1374
C2	1.5639		2.0618	1.3435	2.4457	1.0779	3.1374	2.2413
C3	1.3435	2.0618		1.5639	2.2413	3.1374	1.0779	2.4457
C4	2.0618	1.3435	1.5639		3.1374	2.2413	2.4457	1.0779
H5	1.0779	2.4457	2.2413	3.1374		3.0817	2.8744	4.2141
H6	2.4457	1.0779	3.1374	2.2413	3.0817		4.2141	2.8744
H7	2.2413	3.1374	1.0779	2.4457	2.8744	4.2141		3.0817
H8	3.1374	2.2413	2.4457	1.0779	4.2141	2.8744	3.0817

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.753
C1	C3	C4	90.000	C1	C3	H7	135.247
C2	C1	C3	90.000	C2	C1	H5	134.753
C2	C4	C3	90.000	C3	C1	H5	135.247
C4	C2	H6	135.247	C4	C3	H7	134.753

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: MP2=FULL/6-31G**

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/6-31G**

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)