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	hartrees
Energy at 0K	-154.622590
Energy at 298.15K	-154.625648
HF Energy	-154.622590
Nuclear repulsion energy	98.854708

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3273	3137	0.00
2	A_g	1655	1586	0.00
3	A_g	1127	1080	0.00
4	A_g	974	933	0.00
5	A_u	877	841	0.00
6	A_u	538	516	0.00
7	B_1g	861	825	0.00
8	B_1u	3261	3126	25.82
9	B_1u	1666	1597	2.60
10	B_1u	1067	1023	0.26
11	B_2g	594	569	0.00
12	B_2u	3240	3105	12.63
13	B_2u	1271	1218	36.15
14	B_2u	732	702	7.69
15	B_3g	3223	3089	0.00
16	B_3g	1187	1137	0.00
17	B_3g	838	803	0.00
18	B_3u	591	567	121.57

Atom	y (Å)	z (Å)
C1	0.667	0.786
C2	0.667	-0.786
C3	-0.667	0.786
C4	-0.667	-0.786
H5	1.438	1.547
H6	1.438	-1.547
H7	-1.438	1.547
H8	-1.438	-1.547

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5717	1.3339	2.0615	1.0835	2.4572	2.2382	3.1422
C2	1.5717		2.0615	1.3339	2.4572	1.0835	3.1422	2.2382
C3	1.3339	2.0615		1.5717	2.2382	3.1422	1.0835	2.4572
C4	2.0615	1.3339	1.5717		3.1422	2.2382	2.4572	1.0835
H5	1.0835	2.4572	2.2382	3.1422		3.0945	2.8755	4.2243
H6	2.4572	1.0835	3.1422	2.2382	3.0945		4.2243	2.8755
H7	2.2382	3.1422	1.0835	2.4572	2.8755	4.2243		3.0945
H8	3.1422	2.2382	2.4572	1.0835	4.2243	2.8755	3.0945

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.649
C1	C3	C4	90.000	C1	C3	H7	135.351
C2	C1	C3	90.000	C2	C1	H5	134.649
C2	C4	C3	90.000	C3	C1	H5	135.351
C4	C2	H6	135.351	C4	C3	H7	134.649

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: B3PW91/6-31G**

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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Number	Element	Mulliken
1	C	-0.123
2	C	-0.123
3	C	-0.123
4	C	-0.123
5	H	0.123
6	H	0.123
7	H	0.123
8	H	0.123

<r²>	57.445
(<r²>)^1/2	7.579

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: B3PW91/6-31G**

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)