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	hartrees
Energy at 0K	-154.695335
Energy at 298.15K	-154.698331
HF Energy	-154.695335
Nuclear repulsion energy	98.381622

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3246	3150	0.00
2	A_g	1621	1573	0.00
3	A_g	1104	1072	0.00
4	A_g	950	922	0.00
5	A_u	823	799	0.00
6	A_u	526	511	0.00
7	B_1g	850	825	0.00
8	B_1u	3236	3140	16.55
9	B_1u	1625	1577	8.71
10	B_1u	1046	1015	0.05
11	B_2g	568	551	0.00
12	B_2u	3214	3119	11.01
13	B_2u	1247	1210	39.48
14	B_2u	703	682	9.93
15	B_3g	3198	3103	0.00
16	B_3g	1167	1132	0.00
17	B_3g	845	820	0.00
18	B_3u	563	546	143.83

Atom	y (Å)	z (Å)
C1	0.670	0.790
C2	0.670	-0.790
C3	-0.670	0.790
C4	-0.670	-0.790
H5	1.441	1.559
H6	1.441	-1.559
H7	-1.441	1.559
H8	-1.441	-1.559

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5799	1.3400	2.0716	1.0884	2.4717	2.2461	3.1575
C2	1.5799		2.0716	1.3400	2.4717	1.0884	3.1575	2.2461
C3	1.3400	2.0716		1.5799	2.2461	3.1575	1.0884	2.4717
C4	2.0716	1.3400	1.5799		3.1575	2.2461	2.4717	1.0884
H5	1.0884	2.4717	2.2461	3.1575		3.1172	2.8810	4.2447
H6	2.4717	1.0884	3.1575	2.2461	3.1172		4.2447	2.8810
H7	2.2461	3.1575	1.0884	2.4717	2.8810	4.2447		3.1172
H8	3.1575	2.2461	2.4717	1.0884	4.2447	2.8810	3.1172

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.933
C1	C3	C4	90.000	C1	C3	H7	135.067
C2	C1	C3	90.000	C2	C1	H5	134.933
C2	C4	C3	90.000	C3	C1	H5	135.067
C4	C2	H6	135.067	C4	C3	H7	134.933

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: B3LYPultrafine/aug-cc-pVDZ

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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Number	Element	Mulliken
1	C	0.449
2	C	0.449
3	C	0.449
4	C	0.449
5	H	-0.449
6	H	-0.449
7	H	-0.449
8	H	-0.449

<r²>	58.585
(<r²>)^1/2	7.654

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: B3LYPultrafine/aug-cc-pVDZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)