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	hartrees
Energy at 0K	-153.061824
Energy at 298.15K	-153.060766
HF Energy	-152.502908
Nuclear repulsion energy	75.723398

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)
1	Σ_g	3459	3317
2	Σ_g	2215	2124
3	Σ_g	886	849
4	Σ_u	3459	3317
5	Σ_u	2033	1950
6	Π_g	598	574
6	Π_g	598	574
7	Π_g	459	440
7	Π_g	459	440
8	Π_u	584	560
8	Π_u	584	560
9	Π_u	221	212
9	Π_u	221	212

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.697
C2	0.000	0.000	-0.697
C3	0.000	0.000	1.930
C4	0.000	0.000	-1.930
H5	0.000	0.000	3.009
H6	0.000	0.000	-3.009

	C1	C2	C3	C4	H5	H6
C1		1.3939	1.2331	2.6270	2.3117	3.7056
C2	1.3939		2.6270	1.2331	3.7056	2.3117
C3	1.2331	2.6270		3.8601	1.0786	4.9387
C4	2.6270	1.2331	3.8601		4.9387	1.0786
H5	2.3117	3.7056	1.0786	4.9387		6.0173
H6	3.7056	2.3117	4.9387	1.0786	6.0173

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(T)=FULL/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(T)=FULL/cc-pVDZ

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)