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	hartrees
Energy at 0K	-153.020833
Energy at 298.15K	-153.020007
HF Energy	-152.505559
Nuclear repulsion energy	75.986928

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3485	3334	0.00
2	Σ_g	2296	2197	0.00
3	Σ_g	894	855	0.00
4	Σ_u	3484	3333	155.22
5	Σ_u	2104	2012	0.01
6	Π_g	646	618	0.00
6	Π_g	646	618	0.00
7	Π_g	511	489	0.00
7	Π_g	511	489	0.00
8	Π_u	645	617	76.71
8	Π_u	645	617	76.71
9	Π_u	230	220	5.40
9	Π_u	230	220	5.40

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	1.923
C4	0.000	0.000	-1.923
H5	0.000	0.000	3.000
H6	0.000	0.000	-3.000

	C1	C2	C3	C4	H5	H6
C1		1.3984	1.2238	2.6222	2.3011	3.6995
C2	1.3984		2.6222	1.2238	3.6995	2.3011
C3	1.2238	2.6222		3.8461	1.0773	4.9234
C4	2.6222	1.2238	3.8461		4.9234	1.0773
H5	2.3011	3.6995	1.0773	4.9234		6.0006
H6	3.6995	2.3011	4.9234	1.0773	6.0006

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: CCD/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: CCD/cc-pVDZ

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)