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	hartrees
Energy at 0K	-153.522692
Energy at 298.15K	-153.521792
HF Energy	-153.522692
Nuclear repulsion energy	77.306072

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3467	3350	0.00
2	Σ_g	2287	2210	0.00
3	Σ_g	917	886	0.00
4	Σ_u	3469	3353	149.76
5	Σ_u	2111	2039	1.13
6	Π_g	614	593	0.00
6	Π_g	614	593	0.00
7	Π_g	514	497	0.00
7	Π_g	514	497	0.00
8	Π_u	600	580	91.04
8	Π_u	600	580	91.04
9	Π_u	234	226	5.34
9	Π_u	234	226	5.34

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.682
C2	0.000	0.000	-0.682
C3	0.000	0.000	1.889
C4	0.000	0.000	-1.889
H5	0.000	0.000	2.953
H6	0.000	0.000	-2.953

	C1	C2	C3	C4	H5	H6
C1		1.3648	1.2067	2.5715	2.2704	3.6352
C2	1.3648		2.5715	1.2067	3.6352	2.2704
C3	1.2067	2.5715		3.7782	1.0637	4.8419
C4	2.5715	1.2067	3.7782		4.8419	1.0637
H5	2.2704	3.6352	1.0637	4.8419		5.9056
H6	3.6352	2.2704	4.8419	1.0637	5.9056

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: B3LYP/6-311G*

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	-0.169
2	C	-0.169
3	C	-0.114
4	C	-0.114
5	H	0.283
6	H	0.283

<r²>	78.481
(<r²>)^1/2	8.859

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: B3LYP/6-311G*

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)