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	hartrees
Energy at 0K	-153.460563
Energy at 298.15K	-153.460035
HF Energy	-153.460563
Nuclear repulsion energy	76.756843

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3512	3379	0.00
2	Σ_g	2293	2206	0.00
3	Σ_g	924	889	0.00
4	Σ_u	3513	3380	151.83
5	Σ_u	2092	2013	1.70
6	Π_g	738	710	0.00
6	Π_g	738	710	0.00
7	Π_g	621	597	0.00
7	Π_g	621	597	0.00
8	Π_u	675	649	131.41
8	Π_u	675	649	131.41
9	Π_u	248	239	7.49
9	Π_u	248	239	7.49

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.683
C2	0.000	0.000	-0.683
C3	0.000	0.000	1.904
C4	0.000	0.000	-1.904
H5	0.000	0.000	2.968
H6	0.000	0.000	-2.968

	C1	C2	C3	C4	H5	H6
C1		1.3662	1.2209	2.5871	2.2852	3.6514
C2	1.3662		2.5871	1.2209	3.6514	2.2852
C3	1.2209	2.5871		3.8081	1.0642	4.8723
C4	2.5871	1.2209	3.8081		4.8723	1.0642
H5	2.2852	3.6514	1.0642	4.8723		5.9366
H6	3.6514	2.2852	4.8723	1.0642	5.9366

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: TPSSh/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	0.196
2	C	0.196
3	C	-0.519
4	C	-0.519
5	H	0.323
6	H	0.323

<r²>	79.056
(<r²>)^1/2	8.891

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: TPSSh/6-31G

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)