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	hartrees
Energy at 0K	-153.043887
Energy at 298.15K
HF Energy	-152.508818
Nuclear repulsion energy	75.895178

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3463	3354	0.00
2	Σ_g	2269	2198	0.00
3	Σ_g	886	859	0.00
4	Σ_u	3463	3354	148.46
5	Σ_u	2069	2004	1.25
6	Π_g	575	557	0.00
6	Π_g	575	557	0.00
7	Π_g	612i	593i	0.00
7	Π_g	612i	593i	0.00
8	Π_u	550	533	82.98
8	Π_u	550	533	82.98
9	Π_u	154	150	3.27
9	Π_u	154	150	3.27

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.699
C2	0.000	0.000	-0.699
C3	0.000	0.000	1.926
C4	0.000	0.000	-1.926
H5	0.000	0.000	3.002
H6	0.000	0.000	-3.002

	C1	C2	C3	C4	H5	H6
C1		1.3978	1.2270	2.6248	2.3028	3.7006
C2	1.3978		2.6248	1.2270	3.7006	2.3028
C3	1.2270	2.6248		3.8518	1.0758	4.9276
C4	2.6248	1.2270	3.8518		4.9276	1.0758
H5	2.3028	3.7006	1.0758	4.9276		6.0034
H6	3.7006	2.3028	4.9276	1.0758	6.0034

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: QCISD/aug-cc-pVDZ

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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All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: QCISD/aug-cc-pVDZ

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)