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	hartrees
Energy at 0K	-154.225208
Energy at 298.15K	-154.228011
HF Energy	-153.637583
Nuclear repulsion energy	98.330053

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)
1	A_g	3258	3163
2	A_g	1543	1498
3	A_g	1132	1099
4	A_g	956	928
5	A_u	689	669
6	A_u	474	460
7	B_1g	749	727
8	B_1u	3247	3152
9	B_1u	1588	1542
10	B_1u	1060	1029
11	B_2g	493	478
12	B_2u	3229	3135
13	B_2u	1281	1244
14	B_2u	739	717
15	B_3g	3215	3121
16	B_3g	1179	1144
17	B_3g	869	844
18	B_3u	558	542

Atom	y (Å)	z (Å)
C1	0.676	0.784
C2	0.676	-0.784
C3	-0.676	0.784
C4	-0.676	-0.784
H5	1.450	1.548
H6	1.450	-1.548
H7	-1.450	1.548
H8	-1.450	-1.548

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5687	1.3518	2.0708	1.0869	2.4570	2.2585	3.1554
C2	1.5687		2.0708	1.3518	2.4570	1.0869	3.1554	2.2585
C3	1.3518	2.0708		1.5687	2.2585	3.1554	1.0869	2.4570
C4	2.0708	1.3518	1.5687		3.1554	2.2585	2.4570	1.0869
H5	1.0869	2.4570	2.2585	3.1554		3.0951	2.8996	4.2411
H6	2.4570	1.0869	3.1554	2.2585	3.0951		4.2411	2.8996
H7	2.2585	3.1554	1.0869	2.4570	2.8996	4.2411		3.0951
H8	3.1554	2.2585	2.4570	1.0869	4.2411	2.8996	3.0951

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.601
C1	C3	C4	90.000	C1	C3	H7	135.399
C2	C1	C3	90.000	C2	C1	H5	134.601
C2	C4	C3	90.000	C3	C1	H5	135.399
C4	C2	H6	135.399	C4	C3	H7	134.601

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: CCSD(T)=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: CCSD(T)=FULL/6-31G*

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)