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	hartrees
Energy at 0K	-152.437566
Energy at 298.15K	-152.436704
HF Energy	-152.437566
Nuclear repulsion energy	76.685042

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3418	3387	0.00
2	Σ_g	2242	2221	0.00
3	Σ_g	906	898	0.00
4	Σ_u	3420	3389	157.83
5	Σ_u	2058	2039	0.24
6	Π_g	640	634	0.00
6	Π_g	640	634	0.00
7	Π_g	517	513	0.00
7	Π_g	517	513	0.00
8	Π_u	637	632	100.82
8	Π_u	637	632	100.82
9	Π_u	220	218	7.12
9	Π_u	220	218	7.12

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	1.905
C4	0.000	0.000	-1.905
H5	0.000	0.000	2.975
H6	0.000	0.000	-2.975

	C1	C2	C3	C4	H5	H6
C1		1.3621	1.2237	2.5858	2.2942	3.6563
C2	1.3621		2.5858	1.2237	3.6563	2.2942
C3	1.2237	2.5858		3.8094	1.0705	4.8800
C4	2.5858	1.2237	3.8094		4.8800	1.0705
H5	2.2942	3.6563	1.0705	4.8800		5.9505
H6	3.6563	2.2942	4.8800	1.0705	5.9505

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: PBEPBE/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	0.007
2	C	0.007
3	C	-0.285
4	C	-0.285
5	H	0.278
6	H	0.278

<r²>	79.295
(<r²>)^1/2	8.905

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: PBEPBE/3-21G

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)