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	hartrees
Energy at 0K	-154.391117
Energy at 298.15K	-154.394119
HF Energy	-153.694274
Nuclear repulsion energy	98.449007

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)
1	A_g	3257	3090
2	A_g	1538	1459
3	A_g	1115	1058
4	A_g	945	896
5	A_u	816	774
6	A_u	517	490
7	B_1g	831	788
8	B_1u	3245	3078
9	B_1u	1568	1488
10	B_1u	1049	995
11	B_2g	569	540
12	B_2u	3225	3060
13	B_2u	1268	1202
14	B_2u	718	681
15	B_3g	3211	3046
16	B_3g	1183	1123
17	B_3g	861	817
18	B_3u	579	549

Atom	y (Å)	z (Å)
C1	0.674	0.787
C2	0.674	-0.787
C3	-0.674	0.787
C4	-0.674	-0.787
H5	1.439	1.549
H6	1.439	-1.549
H7	-1.439	1.549
H8	-1.439	-1.549

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5733	1.3479	2.0717	1.0799	2.4577	2.2461	3.1495
C2	1.5733		2.0717	1.3479	2.4577	1.0799	3.1495	2.2461
C3	1.3479	2.0717		1.5733	2.2461	3.1495	1.0799	2.4577
C4	2.0717	1.3479	1.5733		3.1495	2.2461	2.4577	1.0799
H5	1.0799	2.4577	2.2461	3.1495		3.0979	2.8778	4.2283
H6	2.4577	1.0799	3.1495	2.2461	3.0979		4.2283	2.8778
H7	2.2461	3.1495	1.0799	2.4577	2.8778	4.2283		3.0979
H8	3.1495	2.2461	2.4577	1.0799	4.2283	2.8778	3.0979

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.900
C1	C3	C4	90.000	C1	C3	H7	135.100
C2	C1	C3	90.000	C2	C1	H5	134.900
C2	C4	C3	90.000	C3	C1	H5	135.100
C4	C2	H6	135.100	C4	C3	H7	134.900

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: QCISD(T)/cc-pVTZ

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: QCISD(T)/cc-pVTZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)