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	hartrees
Energy at 0K	-153.487630
Energy at 298.15K	-153.486944
HF Energy	-153.487630
Nuclear repulsion energy	77.437507

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3495	3335	0.00
2	Σ_g	2316	2209	0.00
3	Σ_g	926	883	0.00
4	Σ_u	3497	3336	200.81
5	Σ_u	2137	2039	3.00
6	Π_g	674	643	0.00
6	Π_g	674	643	0.00
7	Π_g	539	514	0.00
7	Π_g	539	514	0.00
8	Π_u	683	651	97.52
8	Π_u	683	651	97.52
9	Π_u	239	228	9.35
9	Π_u	239	228	9.35

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	1.886
C4	0.000	0.000	-1.886
H5	0.000	0.000	2.949
H6	0.000	0.000	-2.949

	C1	C2	C3	C4	H5	H6
C1		1.3629	1.2043	2.5672	2.2671	3.6300
C2	1.3629		2.5672	1.2043	3.6300	2.2671
C3	1.2043	2.5672		3.7714	1.0628	4.8342
C4	2.5672	1.2043	3.7714		4.8342	1.0628
H5	2.2671	3.6300	1.0628	4.8342		5.8971
H6	3.6300	2.2671	4.8342	1.0628	5.8971

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/TZVP

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	-0.037
2	C	-0.037
3	C	-0.135
4	C	-0.135
5	H	0.172
6	H	0.172

<r²>	78.260
(<r²>)^1/2	8.846

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: mPW1PW91/TZVP

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)