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	hartrees
Energy at 0K	-153.061055
Energy at 298.15K	-153.060005
HF Energy	-152.503049
Nuclear repulsion energy	75.738506

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)
1	Σ_g	3460	3332
2	Σ_g	2219	2137
3	Σ_g	886	854
4	Σ_u	3460	3333
5	Σ_u	2037	1962
6	Π_g	600	578
6	Π_g	600	578
7	Π_g	460	443
7	Π_g	460	443
8	Π_u	586	564
8	Π_u	586	564
9	Π_u	222	214
9	Π_u	222	214

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.697
C2	0.000	0.000	-0.697
C3	0.000	0.000	1.930
C4	0.000	0.000	-1.930
H5	0.000	0.000	3.008
H6	0.000	0.000	-3.008

	C1	C2	C3	C4	H5	H6
C1		1.3939	1.2327	2.6266	2.3113	3.7052
C2	1.3939		2.6266	1.2327	3.7052	2.3113
C3	1.2327	2.6266		3.8593	1.0786	4.9379
C4	2.6266	1.2327	3.8593		4.9379	1.0786
H5	2.3113	3.7052	1.0786	4.9379		6.0164
H6	3.7052	2.3113	4.9379	1.0786	6.0164

atom1	atom2	atom3	angle		atom1	atom2	atom3	angle
C1	C2	C4	180.000		C1	C3	H5	180.000
C2	C1	C3	180.000		C2	C4	H6	180.000

All results from a given calculation for C₄H₂ (Diacetylene)

using model chemistry: CCSD(T)=FULL/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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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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All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: CCSD(T)=FULL/cc-pVDZ

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)