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	hartrees
Energy at 0K	-153.009337
Energy at 298.15K	-153.008010
HF Energy	-152.494566
Nuclear repulsion energy	76.577526

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3493	3299	0.00
2	Σ_g	2316	2187	0.00
3	Σ_g	902	852	0.00
4	Σ_u	3494	3299	129.28
5	Σ_u	2120	2002	0.05
6	Π_g	606	572	0.00
6	Π_g	606	572	0.00
7	Π_g	353	333	0.00
7	Π_g	353	333	0.00
8	Π_u	513	484	100.86
8	Π_u	513	484	100.86
9	Π_u	239	226	1.26
9	Π_u	239	226	1.26

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	1.908
C4	0.000	0.000	-1.908
H5	0.000	0.000	2.977
H6	0.000	0.000	-2.977

	C1	C2	C3	C4	H5	H6
C1		1.3876	1.2144	2.6020	2.2834	3.6711
C2	1.3876		2.6020	1.2144	3.6711	2.2834
C3	1.2144	2.6020		3.8164	1.0691	4.8854
C4	2.6020	1.2144	3.8164		4.8854	1.0691
H5	2.2834	3.6711	1.0691	4.8854		5.9545
H6	3.6711	2.2834	4.8854	1.0691	5.9545

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/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: CCSD/6-31G*

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)