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	hartrees
Energy at 0K	-153.084460
Energy at 298.15K	-153.083017
HF Energy	-152.547587
Nuclear repulsion energy	76.955960

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3505	3345	0.00
2	Σ_g	2306	2201	0.00
3	Σ_g	895	854	0.00
4	Σ_u	3505	3345	144.66
5	Σ_u	2112	2015	0.62
6	Π_g	608	580	0.00
6	Π_g	608	580	0.00
7	Π_g	304	290	0.00
7	Π_g	304	290	0.00
8	Π_u	599	572	91.28
8	Π_u	599	572	91.28
9	Π_u	186	177	4.06
9	Π_u	186	177	4.06

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.691
C2	0.000	0.000	-0.691
C3	0.000	0.000	1.899
C4	0.000	0.000	-1.899
H5	0.000	0.000	2.962
H6	0.000	0.000	-2.962

	C1	C2	C3	C4	H5	H6
C1		1.3823	1.2079	2.5902	2.2705	3.6529
C2	1.3823		2.5902	1.2079	3.6529	2.2705
C3	1.2079	2.5902		3.7981	1.0626	4.8608
C4	2.5902	1.2079	3.7981		4.8608	1.0626
H5	2.2705	3.6529	1.0626	4.8608		5.9234
H6	3.6529	2.2705	4.8608	1.0626	5.9234

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/TZVP

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/TZVP

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)