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	hartrees
Energy at 0K	-153.298368
Energy at 298.15K	-153.297801
HF Energy	-153.298368
Nuclear repulsion energy	77.072395

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3513	3341	0.00
2	Σ_g	2325	2211	0.00
3	Σ_g	934	888	0.00
4	Σ_u	3515	3343	169.30
5	Σ_u	2144	2039	0.56
6	Π_g	714	679	0.00
6	Π_g	714	679	0.00
7	Π_g	623	592	0.00
7	Π_g	623	592	0.00
8	Π_u	619	588	100.92
8	Π_u	619	588	100.92
9	Π_u	267	254	5.73
9	Π_u	267	254	5.73

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	1.895
C4	0.000	0.000	-1.895
H5	0.000	0.000	2.962
H6	0.000	0.000	-2.962

	C1	C2	C3	C4	H5	H6
C1		1.3672	1.2112	2.5784	2.2782	3.6454
C2	1.3672		2.5784	1.2112	3.6454	2.2782
C3	1.2112	2.5784		3.7896	1.0670	4.8566
C4	2.5784	1.2112	3.7896		4.8566	1.0670
H5	2.2782	3.6454	1.0670	4.8566		5.9237
H6	3.6454	2.2782	4.8566	1.0670	5.9237

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: HSEh1PBE/6-31G*

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	0.624
2	C	0.624
3	C	-0.895
4	C	-0.895
5	H	0.270
6	H	0.270

<r²>	78.416
(<r²>)^1/2	8.855

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: HSEh1PBE/6-31G*

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)