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	hartrees
Energy at 0K	-153.101479
Energy at 298.15K	-153.100481
HF Energy	-152.514777
Nuclear repulsion energy	77.094003

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3533	3346	0.00
2	Σ_g	2343	2219	0.00
3	Σ_g	904	856	0.00
4	Σ_u	3532	3345	164.52
5	Σ_u	2142	2029	0.27
6	Π_g	636	602	0.00
6	Π_g	636	602	0.00
7	Π_g	447	424	0.00
7	Π_g	447	424	0.00
8	Π_u	621	588	76.43
8	Π_u	621	588	76.43
9	Π_u	220	209	4.06
9	Π_u	220	209	4.06

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.690
C2	0.000	0.000	-0.690
C3	0.000	0.000	1.895
C4	0.000	0.000	-1.895
H5	0.000	0.000	2.958
H6	0.000	0.000	-2.958

	C1	C2	C3	C4	H5	H6
C1		1.3797	1.2055	2.5852	2.2677	3.6474
C2	1.3797		2.5852	1.2055	3.6474	2.2677
C3	1.2055	2.5852		3.7908	1.0621	4.8529
C4	2.5852	1.2055	3.7908		4.8529	1.0621
H5	2.2677	3.6474	1.0621	4.8529		5.9150
H6	3.6474	2.2677	4.8529	1.0621	5.9150

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

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)