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	hartrees
Energy at 0K	-154.495981
Energy at 298.15K	-154.499058
HF Energy	-153.706726
Nuclear repulsion energy	99.221110

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3301	3157	0.00
2	A_g	1583	1514	0.00
3	A_g	1128	1078	0.00
4	A_g	973	931	0.00
5	A_u	874	836	0.00
6	A_u	521	498	0.00
7	B_1g	886	848	0.00
8	B_1u	3292	3148	10.64
9	B_1u	1593	1523	4.90
10	B_1u	1064	1018	0.19
11	B_2g	598	572	0.00
12	B_2u	3270	3128	5.25
13	B_2u	1267	1212	34.75
14	B_2u	731	700	8.57
15	B_3g	3255	3114	0.00
16	B_3g	1200	1147	0.00
17	B_3g	858	820	0.00
18	B_3u	593	567	133.13

Atom	y (Å)	z (Å)
C1	0.668	0.780
C2	0.668	-0.780
C3	-0.668	0.780
C4	-0.668	-0.780
H5	1.428	1.541
H6	1.428	-1.541
H7	-1.428	1.541
H8	-1.428	-1.541

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5599	1.3361	2.0539	1.0756	2.4426	2.2297	3.1275
C2	1.5599		2.0539	1.3361	2.4426	1.0756	3.1275	2.2297
C3	1.3361	2.0539		1.5599	2.2297	3.1275	1.0756	2.4426
C4	2.0539	1.3361	1.5599		3.1275	2.2297	2.4426	1.0756
H5	1.0756	2.4426	2.2297	3.1275		3.0830	2.8553	4.2020
H6	2.4426	1.0756	3.1275	2.2297	3.0830		4.2020	2.8553
H7	2.2297	3.1275	1.0756	2.4426	2.8553	4.2020		3.0830
H8	3.1275	2.2297	2.4426	1.0756	4.2020	2.8553	3.0830

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	135.072
C1	C3	C4	90.000	C1	C3	H7	134.928
C2	C1	C3	90.000	C2	C1	H5	135.072
C2	C4	C3	90.000	C3	C1	H5	134.928
C4	C2	H6	134.928	C4	C3	H7	135.072

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: MP2=FULL/aug-cc-pVQZ

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/aug-cc-pVQZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)