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	hartrees
Energy at 0K	-153.011344
Energy at 298.15K	-153.009997
HF Energy	-152.494318
Nuclear repulsion energy	76.535592

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3491	3324	0.00
2	Σ_g	2309	2199	0.00
3	Σ_g	900	857	0.00
4	Σ_u	3491	3325	129.91
5	Σ_u	2112	2011	0.04
6	Π_g	604	575	0.00
6	Π_g	604	575	0.00
7	Π_g	349	332	0.00
7	Π_g	349	332	0.00
8	Π_u	509	485	100.55
8	Π_u	509	485	100.55
9	Π_u	238	226	1.19
9	Π_u	238	226	1.19

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	1.909
C4	0.000	0.000	-1.909
H5	0.000	0.000	2.979
H6	0.000	0.000	-2.979

	C1	C2	C3	C4	H5	H6
C1		1.3878	1.2154	2.6032	2.2846	3.6724
C2	1.3878		2.6032	1.2154	3.6724	2.2846
C3	1.2154	2.6032		3.8186	1.0692	4.8878
C4	2.6032	1.2154	3.8186		4.8878	1.0692
H5	2.2846	3.6724	1.0692	4.8878		5.9571
H6	3.6724	2.2846	4.8878	1.0692	5.9571

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)