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	hartrees
Energy at 0K	-153.185135
Energy at 298.15K	-153.183419
HF Energy	-152.545990
Nuclear repulsion energy	76.779440

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)
1	Σ_g	3482	3328
2	Σ_g	2243	2144
3	Σ_g	890	851
4	Σ_u	3482	3329
5	Σ_u	2060	1970
6	Π_g	574	548
6	Π_g	573	548
7	Π_g	252	240
7	Π_g	252	240
8	Π_u	553	529
8	Π_u	553	529
9	Π_u	173	165
9	Π_u	173	165

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.689
C2	0.000	0.000	-0.689
C3	0.000	0.000	1.904
C4	0.000	0.000	-1.904
H5	0.000	0.000	2.967
H6	0.000	0.000	-2.967

	C1	C2	C3	C4	H5	H6
C1		1.3782	1.2146	2.5928	2.2783	3.6564
C2	1.3782		2.5928	1.2146	3.6564	2.2783
C3	1.2146	2.5928		3.8074	1.0637	4.8710
C4	2.5928	1.2146	3.8074		4.8710	1.0637
H5	2.2783	3.6564	1.0637	4.8710		5.9347
H6	3.6564	2.2783	4.8710	1.0637	5.9347

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/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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All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: CCSD(T)=FULL/TZVP

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)