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	hartrees
Energy at 0K	-153.052761
Energy at 298.15K
HF Energy	-152.509354
Nuclear repulsion energy	75.996467

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3472	3472	0.00
2	Σ_g	2281	2281	0.00
3	Σ_g	891	891	0.00
4	Σ_u	3472	3472	147.64
5	Σ_u	2080	2080	1.34
6	Π_g	585	585	0.00
6	Π_g	585	585	0.00
7	Π_g	600i	600i	0.00
7	Π_g	600i	600i	0.00
8	Π_u	569	569	82.53
8	Π_u	569	569	82.53
9	Π_u	163	163	3.88
9	Π_u	163	163	3.88

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.698
C2	0.000	0.000	-0.698
C3	0.000	0.000	1.923
C4	0.000	0.000	-1.923
H5	0.000	0.000	2.998
H6	0.000	0.000	-2.998

	C1	C2	C3	C4	H5	H6
C1		1.3960	1.2253	2.6212	2.3001	3.6960
C2	1.3960		2.6212	1.2253	3.6960	2.3001
C3	1.2253	2.6212		3.8465	1.0748	4.9213
C4	2.6212	1.2253	3.8465		4.9213	1.0748
H5	2.3001	3.6960	1.0748	4.9213		5.9961
H6	3.6960	2.3001	4.9213	1.0748	5.9961

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: CCSD=FULL/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: CCSD=FULL/aug-cc-pVDZ

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)