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	hartrees
Energy at 0K	-153.026137
Energy at 298.15K	-153.025226
HF Energy	-152.498598
Nuclear repulsion energy	76.556605

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3524	3318	0.00
2	Σ_g	2308	2173	0.00
3	Σ_g	900	847	0.00
4	Σ_u	3524	3317	136.73
5	Σ_u	2111	1988	0.01
6	Π_g	615	579	0.00
6	Π_g	615	579	0.00
7	Π_g	507	478	0.00
7	Π_g	507	478	0.00
8	Π_u	578	544	93.36
8	Π_u	578	544	93.36
9	Π_u	248	233	2.84
9	Π_u	248	233	2.84

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.694
C2	0.000	0.000	-0.694
C3	0.000	0.000	1.910
C4	0.000	0.000	-1.910
H5	0.000	0.000	2.974
H6	0.000	0.000	-2.974

	C1	C2	C3	C4	H5	H6
C1		1.3883	1.2157	2.6040	2.2796	3.6679
C2	1.3883		2.6040	1.2157	3.6679	2.2796
C3	1.2157	2.6040		3.8197	1.0639	4.8836
C4	2.6040	1.2157	3.8197		4.8836	1.0639
H5	2.2796	3.6679	1.0639	4.8836		5.9475
H6	3.6679	2.2796	4.8836	1.0639	5.9475

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/6-31G**

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/6-31G**

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)