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	hartrees
Energy at 0K	-153.508449
Energy at 298.15K	-153.506740
HF Energy	-153.508449
Nuclear repulsion energy	76.715492

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3481	3367	0.00
2	Σ_g	2273	2199	0.00
3	Σ_g	921	891	0.00
4	Σ_u	3482	3369	175.93
5	Σ_u	2091	2023	6.81
6	Π_g	606	586	0.00
6	Π_g	606	586	0.00
7	Π_g	178	173	0.00
7	Π_g	178	173	0.00
8	Π_u	591	571	89.70
8	Π_u	591	571	89.70
9	Π_u	212	205	6.25
9	Π_u	212	205	6.25

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.684
C2	0.000	0.000	-0.684
C3	0.000	0.000	1.904
C4	0.000	0.000	-1.904
H5	0.000	0.000	2.974
H6	0.000	0.000	-2.974

	C1	C2	C3	C4	H5	H6
C1		1.3687	1.2198	2.5884	2.2893	3.6580
C2	1.3687		2.5884	1.2198	3.6580	2.2893
C3	1.2198	2.5884		3.8082	1.0696	4.8777
C4	2.5884	1.2198	3.8082		4.8777	1.0696
H5	2.2893	3.6580	1.0696	4.8777		5.9473
H6	3.6580	2.2893	4.8777	1.0696	5.9473

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: TPSSh/aug-cc-pVDZ

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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Number	Element	Mulliken
1	C	0.377
2	C	0.377
3	C	0.374
4	C	0.374
5	H	-0.752
6	H	-0.752

<r²>	79.558
(<r²>)^1/2	8.920

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: TPSSh/aug-cc-pVDZ

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)