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	hartrees
Energy at 0K	-154.521726
Energy at 298.15K	-154.524657
HF Energy	-154.521726
Nuclear repulsion energy	98.385384

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3177	3142	0.00
2	A_g	1585	1567	0.00
3	A_g	1077	1065	0.00
4	A_g	933	923	0.00
5	A_u	833	824	0.00
6	A_u	505	500	0.00
7	B_1g	834	824	0.00
8	B_1u	3167	3132	21.75
9	B_1u	1588	1570	4.42
10	B_1u	1025	1014	1.02
11	B_2g	565	559	0.00
12	B_2u	3146	3111	11.93
13	B_2u	1214	1201	40.81
14	B_2u	679	672	7.80
15	B_3g	3130	3095	0.00
16	B_3g	1146	1133	0.00
17	B_3g	814	805	0.00
18	B_3u	560	554	137.84

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	1.443	1.557
H6	1.443	-1.557
H7	-1.443	1.557
H8	-1.443	-1.557

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5801	1.3394	2.0714	1.0889	2.4710	2.2473	3.1576
C2	1.5801		2.0714	1.3394	2.4710	1.0889	3.1576	2.2473
C3	1.3394	2.0714		1.5801	2.2473	3.1576	1.0889	2.4710
C4	2.0714	1.3394	1.5801		3.1576	2.2473	2.4710	1.0889
H5	1.0889	2.4710	2.2473	3.1576		3.1139	2.8854	4.2452
H6	2.4710	1.0889	3.1576	2.2473	3.1139		4.2452	2.8854
H7	2.2473	3.1576	1.0889	2.4710	2.8854	4.2452		3.1139
H8	3.1576	2.2473	2.4710	1.0889	4.2452	2.8854	3.1139

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.773
C1	C3	C4	90.000	C1	C3	H7	135.227
C2	C1	C3	90.000	C2	C1	H5	134.773
C2	C4	C3	90.000	C3	C1	H5	135.227
C4	C2	H6	135.227	C4	C3	H7	134.773

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: PBEPBE/TZVP

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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Calc. vs exp. Bad Vib. HF vs MP2 Bad scale factors Low excited states Oddities NaCN Is not linear FAQ Help Units Choose Units Energy Bond length Rotational Constant Moment of Inertia Dipole and Quadrupole Polarizability Explanations Hartree cm-1 Debye Credits Just show me Show me a calculated geometry Summary Using older interface Limit Basis sets Method options List Recent molecules Choose a few Molecules Number of atoms By heavy atoms Diatomics InChI Deuterated Dimers Geometry Point group Point group count Bonds types Isodesmic reactions Bad point group Multiple conformers, states Vibrations Big anharmonicity Energy Enthalpy at 0 Kelvin Similar molecules Similar Isomers Cis/trans Tautomers Multiple conformers, states Ions, Dipoles, etc. List Ions Ionization changes point group Dipole Quadrupole Polarizability Proton Affinities Index of CCCBDB Feedback Error form Wants
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Number	Element	Mulliken
1	C	-0.125
2	C	-0.125
3	C	-0.125
4	C	-0.125
5	H	0.125
6	H	0.125
7	H	0.125
8	H	0.125

<r²>	58.417
(<r²>)^1/2	7.643

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: PBEPBE/TZVP

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)