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	hartrees
Energy at 0K	-153.094300
Energy at 298.15K	-153.093067
HF Energy	-152.511236
Nuclear repulsion energy	76.838280

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3532	3336	0.00
2	Σ_g	2228	2104	0.00
3	Σ_g	906	856	0.00
4	Σ_u	3532	3336	187.14
5	Σ_u	2031	1919	0.52
6	Π_g	586	554	0.00
6	Π_g	586	554	0.00
7	Π_g	413	390	0.00
7	Π_g	413	390	0.00
8	Π_u	544	514	76.74
8	Π_u	544	514	76.74
9	Π_u	213	201	2.60
9	Π_u	213	201	2.60

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.683
C2	0.000	0.000	-0.683
C3	0.000	0.000	1.902
C4	0.000	0.000	-1.902
H5	0.000	0.000	2.964
H6	0.000	0.000	-2.964

	C1	C2	C3	C4	H5	H6
C1		1.3659	1.2193	2.5853	2.2812	3.6471
C2	1.3659		2.5853	1.2193	3.6471	2.2812
C3	1.2193	2.5853		3.8046	1.0618	4.8664
C4	2.5853	1.2193	3.8046		4.8664	1.0618
H5	2.2812	3.6471	1.0618	4.8664		5.9283
H6	3.6471	2.2812	4.8664	1.0618	5.9283

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: MP2/6-31G(2df,p)

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: MP2/6-31G(2df,p)

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)