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	hartrees
Energy at 0K	-154.304580
Energy at 298.15K	-154.307526
HF Energy	-153.676377
Nuclear repulsion energy	98.525958

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3291	3122	0.00
2	A_g	1574	1493	0.00
3	A_g	1130	1072	0.00
4	A_g	976	926	0.00
5	A_u	773	733	0.00
6	A_u	480	455	0.00
7	B_1g	834	791	0.00
8	B_1u	3280	3112	17.65
9	B_1u	1584	1503	2.36
10	B_1u	1056	1002	0.51
11	B_2g	539	511	0.00
12	B_2u	3259	3091	8.65
13	B_2u	1265	1200	33.00
14	B_2u	741	703	6.81
15	B_3g	3245	3078	0.00
16	B_3g	1188	1127	0.00
17	B_3g	852	808	0.00
18	B_3u	567	538	135.47

Atom	y (Å)	z (Å)
C1	0.673	0.785
C2	0.673	-0.785
C3	-0.673	0.785
C4	-0.673	-0.785
H5	1.441	1.548
H6	1.441	-1.548
H7	-1.441	1.548
H8	-1.441	-1.548

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5706	1.3462	2.0686	1.0825	2.4568	2.2474	3.1488
C2	1.5706		2.0686	1.3462	2.4568	1.0825	3.1488	2.2474
C3	1.3462	2.0686		1.5706	2.2474	3.1488	1.0825	2.4568
C4	2.0686	1.3462	1.5706		3.1488	2.2474	2.4568	1.0825
H5	1.0825	2.4568	2.2474	3.1488		3.0969	2.8816	4.2302
H6	2.4568	1.0825	3.1488	2.2474	3.0969		4.2302	2.8816
H7	2.2474	3.1488	1.0825	2.4568	2.8816	4.2302		3.0969
H8	3.1488	2.2474	2.4568	1.0825	4.2302	2.8816	3.0969

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.828
C1	C3	C4	90.000	C1	C3	H7	135.172
C2	C1	C3	90.000	C2	C1	H5	134.828
C2	C4	C3	90.000	C3	C1	H5	135.172
C4	C2	H6	135.172	C4	C3	H7	134.828

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: MP2=FULL/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: MP2=FULL/6-311G**

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)