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	hartrees
Energy at 0K	-22.882462
Energy at 298.15K	-22.881991
HF Energy	-22.882462
Nuclear repulsion energy	36.325465

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3675	3312	0.00
2	Σ_g	2477	2232	0.00
3	Σ_g	942	849	0.00
4	Σ_u	3672	3310	205.85
5	Σ_u	2245	2023	3.47
6	Π_g	810	730	0.00
6	Π_g	810	730	0.00
7	Π_g	522	470	0.00
7	Π_g	522	470	0.00
8	Π_u	820	739	148.37
8	Π_u	820	739	148.37
9	Π_u	254	229	12.96
9	Π_u	254	229	12.96

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.706
C2	0.000	0.000	-0.706
C3	0.000	0.000	1.935
C4	0.000	0.000	-1.935
H5	0.000	0.000	2.992
H6	0.000	0.000	-2.992

	C1	C2	C3	C4	H5	H6
C1		1.4115	1.2293	2.6408	2.2859	3.6974
C2	1.4115		2.6408	1.2293	3.6974	2.2859
C3	1.2293	2.6408		3.8700	1.0566	4.9266
C4	2.6408	1.2293	3.8700		4.9266	1.0566
H5	2.2859	3.6974	1.0566	4.9266		5.9832
H6	3.6974	2.2859	4.9266	1.0566	5.9832

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: HF/CEP-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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Number	Element	Mulliken
1	C	0.197
2	C	0.197
3	C	-0.577
4	C	-0.577
5	H	0.380
6	H	0.380

<r²>	64.774
(<r²>)^1/2	8.048

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: HF/CEP-31G

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)