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	hartrees
Energy at 0K	-152.570698
Energy at 298.15K	-152.570260
HF Energy	-152.570698
Nuclear repulsion energy	77.141410

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3550	3403	0.00
2	Σ_g	2380	2281	0.00
3	Σ_g	916	878	0.00
4	Σ_u	3549	3403	159.73
5	Σ_u	2177	2087	0.01
6	Π_g	813	779	0.00
6	Π_g	813	779	0.00
7	Π_g	565	542	0.00
7	Π_g	565	542	0.00
8	Π_u	810	777	98.14
8	Π_u	810	777	98.14
9	Π_u	244	234	8.46
9	Π_u	244	234	8.46

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.687
C2	0.000	0.000	-0.687
C3	0.000	0.000	1.894
C4	0.000	0.000	-1.894
H5	0.000	0.000	2.956
H6	0.000	0.000	-2.956

	C1	C2	C3	C4	H5	H6
C1		1.3746	1.2067	2.5813	2.2688	3.6433
C2	1.3746		2.5813	1.2067	3.6433	2.2688
C3	1.2067	2.5813		3.7881	1.0620	4.8501
C4	2.5813	1.2067	3.7881		4.8501	1.0620
H5	2.2688	3.6433	1.0620	4.8501		5.9121
H6	3.6433	2.2688	4.8501	1.0620	5.9121

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: M06-2X/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	-0.016
2	C	-0.016
3	C	-0.286
4	C	-0.286
5	H	0.301
6	H	0.301

<r²>	78.749
(<r²>)^1/2	8.874

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: M06-2X/3-21G

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)