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	hartrees
Energy at 0K	-23.272886
Energy at 298.15K	-23.272454
HF Energy	-22.913646
Nuclear repulsion energy	36.043963

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3414	3332	0.00
2	Σ_g	2134	2083	0.00
3	Σ_g	845	825	0.00
4	Σ_u	3413	3332	102.24
5	Σ_u	1916	1870	0.58
6	Π_g	788	769	0.00
6	Π_g	788	769	0.00
7	Π_g	516	503	0.00
7	Π_g	516	503	0.00
8	Π_u	800	781	158.44
8	Π_u	800	781	158.44
9	Π_u	280	274	12.91
9	Π_u	280	274	12.91

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.703
C2	0.000	0.000	-0.703
C3	0.000	0.000	1.948
C4	0.000	0.000	-1.948
H5	0.000	0.000	3.019
H6	0.000	0.000	-3.019

	C1	C2	C3	C4	H5	H6
C1		1.4059	1.2451	2.6510	2.3156	3.7215
C2	1.4059		2.6510	1.2451	3.7215	2.3156
C3	1.2451	2.6510		3.8961	1.0705	4.9666
C4	2.6510	1.2451	3.8961		4.9666	1.0705
H5	2.3156	3.7215	1.0705	4.9666		6.0370
H6	3.7215	2.3156	4.9666	1.0705	6.0370

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: MP2/CEP-121G

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: MP2/CEP-121G

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)