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	hartrees
Energy at 0K	-153.212295
Energy at 298.15K	-153.211510
HF Energy	-152.549190
Nuclear repulsion energy	77.133266

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3494	3317	0.00
2	Σ_g	2213	2101	0.00
3	Σ_g	900	854	0.00
4	Σ_u	3474	3298	170.67
5	Σ_u	2022	1919	0.09
6	Π_g	641	609	0.00
6	Π_g	641	609	0.00
7	Π_g	499	474	0.00
7	Π_g	499	474	0.00
8	Π_u	669	635	81.04
8	Π_u	669	635	81.04
9	Π_u	242	229	7.73
9	Π_u	242	229	7.73

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.680
C2	0.000	0.000	-0.680
C3	0.000	0.000	1.895
C4	0.000	0.000	-1.895
H5	0.000	0.000	2.953
H6	0.000	0.000	-2.953

	C1	C2	C3	C4	H5	H6
C1		1.3607	1.2147	2.5753	2.2725	3.6332
C2	1.3607		2.5753	1.2147	3.6332	2.2725
C3	1.2147	2.5753		3.7900	1.0578	4.8478
C4	2.5753	1.2147	3.7900		4.8478	1.0578
H5	2.2725	3.6332	1.0578	4.8478		5.9057
H6	3.6332	2.2725	4.8478	1.0578	5.9057

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: MP2=FULL/cc-pVTZ

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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All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: MP2=FULL/cc-pVTZ

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)