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	hartrees
Energy at 0K	-151.531320
Energy at 298.15K	-151.530493
HF Energy	-151.531320
Nuclear repulsion energy	76.635124

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3716	3266	0.00
2	Σ_g	2471	2172	0.00
3	Σ_g	938	824	0.00
4	Σ_u	3714	3264	408.76
5	Σ_u	2306	2027	47.20
6	Π_g	741	651	0.00
6	Π_g	741	651	0.00
7	Π_g	574	505	0.00
7	Π_g	574	505	0.00
8	Π_u	743	653	36.07
8	Π_u	743	653	36.07
9	Π_u	241	211	3.25
9	Π_u	241	211	3.25

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.697
C2	0.000	0.000	-0.697
C3	0.000	0.000	1.905
C4	0.000	0.000	-1.905
H5	0.000	0.000	2.984
H6	0.000	0.000	-2.984

	C1	C2	C3	C4	H5	H6
C1		1.3933	1.2080	2.6012	2.2874	3.6806
C2	1.3933		2.6012	1.2080	3.6806	2.2874
C3	1.2080	2.6012		3.8092	1.0794	4.8886
C4	2.6012	1.2080	3.8092		4.8886	1.0794
H5	2.2874	3.6806	1.0794	4.8886		5.9680
H6	3.6806	2.2874	4.8886	1.0794	5.9680

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: mPW1PW91/STO-3G

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	-0.035
2	C	-0.035
3	C	-0.099
4	C	-0.099
5	H	0.134
6	H	0.134

<r²>	78.643
(<r²>)^1/2	8.868

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: mPW1PW91/STO-3G

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)