Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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All data (experiment and calculated) in the CCCBDB for C₄H₂ (Diacetylene)

Property		Experiment	Calculated	Comparison
Energies Entropies	Enthalpy 298.15K	x
	Enthalpy 0K
	Energy 0K		507
	Energy 298.15K		431
	Atomization Enthalpy 298.15K	x	36	x
	Atomization Enthalpy 0K		36
	Entropy (298.15K)		8
	Entropy at any temperature		8
	Integrated Heat Capacity		8
	Heat Capacity (Cp)	x	8	x
	Nuclear Repulsion Energy		478
	HOMO-LUMO Energies		426
	Barriers to Internal Rotation		0
Geometries	Cartesians	x	460
	Internal Coordinates	x	459	x
	Products of moments of inertia	x	460	x
	Rotational Constants	x	469	x
	Point Group		483
Vibrations	Vibrational Frequencies	fun.	461	x
	Vibrational Intensities		613
	Zero-point energies	x	461	x
	Vibrational scaling factors	x
	Anharmonic frequencies and constants
	Raman frequencies and intensities		5
Electronic States	Electronic states	x	0
Electrostatics	Atom charges		275
	Dipole	x	374	x
	Quadrupole		303
	Polarizability	x	342	x
Other results	Spin		8
	Number of basis functions		68
	Conformations		2	x