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	hartrees
Energy at 0K	-153.489017
Energy at 298.15K	-153.488336
HF Energy	-153.489017
Nuclear repulsion energy	77.503959

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3488	3345	0.00
2	Σ_g	2310	2216	0.00
3	Σ_g	924	886	0.00
4	Σ_u	3488	3346	187.30
5	Σ_u	2132	2045	2.43
6	Π_g	677	649	0.00
6	Π_g	677	649	0.00
7	Π_g	537	515	0.00
7	Π_g	537	515	0.00
8	Π_u	681	653	89.75
8	Π_u	681	653	89.75
9	Π_u	240	230	8.15
9	Π_u	240	230	8.15

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	1.884
C4	0.000	0.000	-1.884
H5	0.000	0.000	2.946
H6	0.000	0.000	-2.946

	C1	C2	C3	C4	H5	H6
C1		1.3628	1.2027	2.5655	2.2646	3.6274
C2	1.3628		2.5655	1.2027	3.6274	2.2646
C3	1.2027	2.5655		3.7682	1.0619	4.8301
C4	2.5655	1.2027	3.7682		4.8301	1.0619
H5	2.2646	3.6274	1.0619	4.8301		5.8921
H6	3.6274	2.2646	4.8301	1.0619	5.8921

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/cc-pVTZ

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	0.460
2	C	0.460
3	C	-0.578
4	C	-0.578
5	H	0.118
6	H	0.118

<r²>	78.115
(<r²>)^1/2	8.838

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: mPW1PW91/cc-pVTZ

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)