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	hartrees
Energy at 0K	-152.642411
Energy at 298.15K	-152.641745
HF Energy	-152.642411
Nuclear repulsion energy	77.207381

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3493	3370	0.00
2	Σ_g	2316	2235	0.00
3	Σ_g	915	883	0.00
4	Σ_u	3494	3371	161.92
5	Σ_u	2130	2055	0.07
6	Π_g	709	684	0.00
6	Π_g	709	684	0.00
7	Π_g	546	527	0.00
7	Π_g	546	527	0.00
8	Π_u	705	681	100.58
8	Π_u	705	681	100.58
9	Π_u	228	220	7.64
9	Π_u	228	220	7.64

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	1.892
C4	0.000	0.000	-1.892
H5	0.000	0.000	2.954
H6	0.000	0.000	-2.954

	C1	C2	C3	C4	H5	H6
C1		1.3628	1.2108	2.5735	2.2726	3.6354
C2	1.3628		2.5735	1.2108	3.6354	2.2726
C3	1.2108	2.5735		3.7843	1.0619	4.8462
C4	2.5735	1.2108	3.7843		4.8462	1.0619
H5	2.2726	3.6354	1.0619	4.8462		5.9080
H6	3.6354	2.2726	4.8462	1.0619	5.9080

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: B3LYPultrafine/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	0.009
2	C	0.009
3	C	-0.288
4	C	-0.288
5	H	0.279
6	H	0.279

<r²>	78.507
(<r²>)^1/2	8.860

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: B3LYPultrafine/3-21G

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)