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	hartrees
Energy at 0K	-23.618635
Energy at 298.15K	-23.617883
HF Energy	-23.618635
Nuclear repulsion energy	36.012809

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3476	3357	0.00
2	Σ_g	2293	2214	0.00
3	Σ_g	916	884	0.00
4	Σ_u	3478	3358	205.97
5	Σ_u	2100	2028	2.56
6	Π_g	642	620	0.00
6	Π_g	642	620	0.00
7	Π_g	549	531	0.00
7	Π_g	549	531	0.00
8	Π_u	634	612	147.99
8	Π_u	634	612	148.00
9	Π_u	253	244	4.49
9	Π_u	253	244	4.49

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.698
C2	0.000	0.000	-0.698
C3	0.000	0.000	1.949
C4	0.000	0.000	-1.949
H5	0.000	0.000	3.022
H6	0.000	0.000	-3.022

	C1	C2	C3	C4	H5	H6
C1		1.3964	1.2511	2.6475	2.3235	3.7199
C2	1.3964		2.6475	1.2511	3.7199	2.3235
C3	1.2511	2.6475		3.8987	1.0723	4.9710
C4	2.6475	1.2511	3.8987		4.9710	1.0723
H5	2.3235	3.7199	1.0723	4.9710		6.0433
H6	3.7199	2.3235	4.9710	1.0723	6.0433

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: B3LYP/CEP-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	-0.238
2	C	-0.238
3	C	-0.182
4	C	-0.182
5	H	0.421
6	H	0.421

<r²>	65.171
(<r²>)^1/2	8.073

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: B3LYP/CEP-31G*

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)