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	hartrees
Energy at 0K	-153.292049
Energy at 298.15K	-153.291261
HF Energy	-153.292049
Nuclear repulsion energy	76.285081

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3416	3396	0.00
2	Σ_g	2226	2213	0.00
3	Σ_g	918	913	0.00
4	Σ_u	3418	3398	200.07
5	Σ_u	2048	2036	2.11
6	Π_g	621	618	0.00
6	Π_g	621	618	0.00
7	Π_g	568	564	0.00
7	Π_g	568	564	0.00
8	Π_u	603	600	80.60
8	Π_u	603	600	80.60
9	Π_u	239	238	5.50
9	Π_u	239	238	5.50

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.684
C2	0.000	0.000	-0.684
C3	0.000	0.000	1.914
C4	0.000	0.000	-1.914
H5	0.000	0.000	2.993
H6	0.000	0.000	-2.993

	C1	C2	C3	C4	H5	H6
C1		1.3680	1.2301	2.5981	2.3093	3.6773
C2	1.3680		2.5981	1.2301	3.6773	2.3093
C3	1.2301	2.5981		3.8281	1.0792	4.9073
C4	2.5981	1.2301	3.8281		4.9073	1.0792
H5	2.3093	3.6773	1.0792	4.9073		5.9866
H6	3.6773	2.3093	4.9073	1.0792	5.9866

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: PBEPBEultrafine/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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Number	Element	Mulliken
1	C	0.679
2	C	0.679
3	C	-0.660
4	C	-0.660
5	H	-0.019
6	H	-0.019

<r²>	79.995
(<r²>)^1/2	8.944

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: PBEPBEultrafine/cc-pVDZ

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)