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	hartrees
Energy at 0K	-152.588673
Energy at 298.15K	-152.588064
HF Energy	-152.588673
Nuclear repulsion energy	77.267831

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3512	3352	0.00
2	Σ_g	2340	2234	0.00
3	Σ_g	923	881	0.00
4	Σ_u	3512	3353	167.02
5	Σ_u	2143	2045	0.07
6	Π_g	737	703	0.00
6	Π_g	737	703	0.00
7	Π_g	554	529	0.00
7	Π_g	554	529	0.00
8	Π_u	732	698	108.58
8	Π_u	732	698	108.58
9	Π_u	227	217	9.08
9	Π_u	227	217	9.08

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.681
C2	0.000	0.000	-0.681
C3	0.000	0.000	1.890
C4	0.000	0.000	-1.890
H5	0.000	0.000	2.952
H6	0.000	0.000	-2.952

	C1	C2	C3	C4	H5	H6
C1		1.3615	1.2097	2.5713	2.2716	3.6331
C2	1.3615		2.5713	1.2097	3.6331	2.2716
C3	1.2097	2.5713		3.7810	1.0619	4.8429
C4	2.5713	1.2097	3.7810		4.8429	1.0619
H5	2.2716	3.6331	1.0619	4.8429		5.9047
H6	3.6331	2.2716	4.8429	1.0619	5.9047

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: mPW1PW91/3-21G

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	-0.040
2	C	-0.040
3	C	-0.278
4	C	-0.278
5	H	0.319
6	H	0.319

<r²>	78.354
(<r²>)^1/2	8.852

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: mPW1PW91/3-21G

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)