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	hartrees
Energy at 0K	-153.448246
Energy at 298.15K	-153.447503
HF Energy	-153.448246
Nuclear repulsion energy	77.408459

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3525	3365	0.00
2	Σ_g	2329	2224	0.00
3	Σ_g	929	887	0.00
4	Σ_u	3526	3366	188.88
5	Σ_u	2144	2047	0.28
6	Π_g	654	624	0.00
6	Π_g	654	624	0.00
7	Π_g	547	522	0.00
7	Π_g	547	522	0.00
8	Π_u	637	608	78.58
8	Π_u	637	608	78.58
9	Π_u	241	230	5.89
9	Π_u	241	230	5.89

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	1.887
C4	0.000	0.000	-1.887
H5	0.000	0.000	2.949
H6	0.000	0.000	-2.949

	C1	C2	C3	C4	H5	H6
C1		1.3627	1.2053	2.5679	2.2676	3.6303
C2	1.3627		2.5679	1.2053	3.6303	2.2676
C3	1.2053	2.5679		3.7732	1.0623	4.8355
C4	2.5679	1.2053	3.7732		4.8355	1.0623
H5	2.2676	3.6303	1.0623	4.8355		5.8978
H6	3.6303	2.2676	4.8355	1.0623	5.8978

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: mPW1PW91/6-31G(2df,p)

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	-0.415
4	C	-0.415
5	H	0.219
6	H	0.219

<r²>	77.862
(<r²>)^1/2	8.824

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: mPW1PW91/6-31G(2df,p)

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)