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	hartrees
Energy at 0K	-152.458782
Energy at 298.15K	-152.458561
HF Energy	-152.458782
Nuclear repulsion energy	77.229986

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3686	3319	0.00
2	Σ_g	2490	2242	0.00
3	Σ_g	943	849	0.00
4	Σ_u	3683	3316	172.57
5	Σ_u	2250	2026	4.25
6	Π_g	861	775	0.00
6	Π_g	861	775	0.00
7	Π_g	625	563	0.00
7	Π_g	625	563	0.00
8	Π_u	857	772	132.01
8	Π_u	857	772	132.01
9	Π_u	280	252	13.77
9	Π_u	280	252	13.77

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.693
C2	0.000	0.000	-0.693
C3	0.000	0.000	1.894
C4	0.000	0.000	-1.894
H5	0.000	0.000	2.947
H6	0.000	0.000	-2.947

	C1	C2	C3	C4	H5	H6
C1		1.3867	1.2003	2.5870	2.2537	3.6404
C2	1.3867		2.5870	1.2003	3.6404	2.2537
C3	1.2003	2.5870		3.7873	1.0534	4.8407
C4	2.5870	1.2003	3.7873		4.8407	1.0534
H5	2.2537	3.6404	1.0534	4.8407		5.8941
H6	3.6404	2.2537	4.8407	1.0534	5.8941

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: HF/SDD

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	0.090
2	C	0.090
3	C	-0.360
4	C	-0.360
5	H	0.270
6	H	0.270

<r²>	79.097
(<r²>)^1/2	8.894

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: HF/SDD

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)