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	hartrees
Energy at 0K	-154.233832
Energy at 298.15K	-154.236759
HF Energy	-153.667633
Nuclear repulsion energy	98.325269

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3254	3116	0.00
2	A_g	1585	1517	0.00
3	A_g	1133	1084	0.00
4	A_g	966	925	0.00
5	A_u	739	708	0.00
6	A_u	500	479	0.00
7	B_1g	799	765	0.00
8	B_1u	3242	3104	23.85
9	B_1u	1605	1537	2.56
10	B_1u	1053	1009	0.66
11	B_2g	532	509	0.00
12	B_2u	3222	3085	14.61
13	B_2u	1276	1222	33.93
14	B_2u	748	716	9.29
15	B_3g	3208	3071	0.00
16	B_3g	1174	1124	0.00
17	B_3g	865	829	0.00
18	B_3u	573	549	143.42

Atom	y (Å)	z (Å)
C1	0.673	0.788
C2	0.673	-0.788
C3	-0.673	0.788
C4	-0.673	-0.788
H5	1.443	1.553
H6	1.443	-1.553
H7	-1.443	1.553
H8	-1.443	-1.553

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5761	1.3468	2.0732	1.0851	2.4641	2.2505	3.1559
C2	1.5761		2.0732	1.3468	2.4641	1.0851	3.1559	2.2505
C3	1.3468	2.0732		1.5761	2.2505	3.1559	1.0851	2.4641
C4	2.0732	1.3468	1.5761		3.1559	2.2505	2.4641	1.0851
H5	1.0851	2.4641	2.2505	3.1559		3.1054	2.8865	4.2398
H6	2.4641	1.0851	3.1559	2.2505	3.1054		4.2398	2.8865
H7	2.2505	3.1559	1.0851	2.4641	2.8865	4.2398		3.1054
H8	3.1559	2.2505	2.4641	1.0851	4.2398	2.8865	3.1054

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.805
C1	C3	C4	90.000	C1	C3	H7	135.195
C2	C1	C3	90.000	C2	C1	H5	134.805
C2	C4	C3	90.000	C3	C1	H5	135.195
C4	C2	H6	135.195	C4	C3	H7	134.805

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: QCISD/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: QCISD/6-311G*

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)