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	hartrees
Energy at 0K	-152.645305
Energy at 298.15K	-152.644598
HF Energy	-152.645305
Nuclear repulsion energy	77.040318

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3482	3363	0.00
2	Σ_g	2293	2214	0.00
3	Σ_g	913	882	0.00
4	Σ_u	3484	3364	146.24
5	Σ_u	2102	2030	0.38
6	Π_g	698	674	0.00
6	Π_g	698	674	0.00
7	Π_g	544	525	0.00
7	Π_g	544	525	0.00
8	Π_u	693	670	107.49
8	Π_u	693	670	107.49
9	Π_u	225	218	8.05
9	Π_u	225	218	8.05

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.681
C2	0.000	0.000	-0.681
C3	0.000	0.000	1.896
C4	0.000	0.000	-1.896
H5	0.000	0.000	2.960
H6	0.000	0.000	-2.960

	C1	C2	C3	C4	H5	H6
C1		1.3617	1.2156	2.5773	2.2788	3.6405
C2	1.3617		2.5773	1.2156	3.6405	2.2788
C3	1.2156	2.5773		3.7929	1.0632	4.8561
C4	2.5773	1.2156	3.7929		4.8561	1.0632
H5	2.2788	3.6405	1.0632	4.8561		5.9193
H6	3.6405	2.2788	4.8561	1.0632	5.9193

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/3-21G*

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	-0.047
2	C	-0.047
3	C	-0.265
4	C	-0.265
5	H	0.313
6	H	0.313

<r²>	78.744
(<r²>)^1/2	8.874

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: TPSSh/3-21G*

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)