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	hartrees
Energy at 0K	-154.189769
Energy at 298.15K	-154.192762
HF Energy	-153.653206
Nuclear repulsion energy	97.910925

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3299	3135	0.00
2	A_g	1578	1500	0.00
3	A_g	1125	1070	0.00
4	A_g	965	917	0.00
5	A_u	814	773	0.00
6	A_u	509	484	0.00
7	B_1g	836	795	0.00
8	B_1u	3287	3124	15.46
9	B_1u	1589	1510	1.95
10	B_1u	1047	995	0.41
11	B_2g	566	538	0.00
12	B_2u	3266	3104	6.62
13	B_2u	1263	1201	32.20
14	B_2u	729	693	6.80
15	B_3g	3253	3091	0.00
16	B_3g	1182	1123	0.00
17	B_3g	850	808	0.00
18	B_3u	573	545	115.19

Atom	y (Å)	z (Å)
C1	0.678	0.789
C2	0.678	-0.789
C3	-0.678	0.789
C4	-0.678	-0.789
H5	1.450	1.561
H6	1.450	-1.561
H7	-1.450	1.561
H8	-1.450	-1.561

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5773	1.3560	2.0800	1.0918	2.4728	2.2637	3.1697
C2	1.5773		2.0800	1.3560	2.4728	1.0918	3.1697	2.2637
C3	1.3560	2.0800		1.5773	2.2637	3.1697	1.0918	2.4728
C4	2.0800	1.3560	1.5773		3.1697	2.2637	2.4728	1.0918
H5	1.0918	2.4728	2.2637	3.1697		3.1212	2.9000	4.2605
H6	2.4728	1.0918	3.1697	2.2637	3.1212		4.2605	2.9000
H7	2.2637	3.1697	1.0918	2.4728	2.9000	4.2605		3.1212
H8	3.1697	2.2637	2.4728	1.0918	4.2605	2.9000	3.1212

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.999
C1	C3	C4	90.000	C1	C3	H7	135.001
C2	C1	C3	90.000	C2	C1	H5	134.999
C2	C4	C3	90.000	C3	C1	H5	135.001
C4	C2	H6	135.001	C4	C3	H7	134.999

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: MP2=FULL/cc-pVDZ

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-pVDZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)