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	hartrees
Energy at 0K	-152.551329
Energy at 298.15K	-152.551002
HF Energy	-152.551329
Nuclear repulsion energy	77.951133

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3613	3283	0.00
2	Σ_g	2475	2249	0.00
3	Σ_g	932	847	0.00
4	Σ_u	3612	3282	180.25
5	Σ_u	2280	2072	2.23
6	Π_g	822	747	0.00
6	Π_g	822	747	0.00
7	Π_g	603	548	0.00
7	Π_g	603	548	0.00
8	Π_u	823	747	91.58
8	Π_u	823	747	91.58
9	Π_u	257	234	12.46
9	Π_u	257	234	12.46

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.692
C2	0.000	0.000	-0.692
C3	0.000	0.000	1.874
C4	0.000	0.000	-1.874
H5	0.000	0.000	2.929
H6	0.000	0.000	-2.929

	C1	C2	C3	C4	H5	H6
C1		1.3846	1.1819	2.5665	2.2364	3.6210
C2	1.3846		2.5665	1.1819	3.6210	2.2364
C3	1.1819	2.5665		3.7484	1.0545	4.8029
C4	2.5665	1.1819	3.7484		4.8029	1.0545
H5	2.2364	3.6210	1.0545	4.8029		5.8574
H6	3.6210	2.2364	4.8029	1.0545	5.8574

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/6-311+G(3df,2p)

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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Number	Element	Mulliken
1	C	-0.196
2	C	-0.196
3	C	-0.037
4	C	-0.037
5	H	0.232
6	H	0.232

<r²>	77.885
(<r²>)^1/2	8.825

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: HF/6-311+G(3df,2p)

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)