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	hartrees
Energy at 0K	-152.434547
Energy at 298.15K	-152.433060
HF Energy	-152.305982
Nuclear repulsion energy	76.923814

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3499	3499	0.00
2	Σ_g	2272	2272	0.00
3	Σ_g	900	900	0.00
4	Σ_u	3499	3499	148.64
5	Σ_u	2081	2081	0.01
6	Π_g	646	646	0.00
6	Π_g	646	646	0.00
7	Π_g	232	232	0.00
7	Π_g	232	232	0.00
8	Π_u	654	654	101.41
8	Π_u	654	654	101.41
9	Π_u	205	205	5.47
9	Π_u	205	205	5.47

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.684
C2	0.000	0.000	-0.684
C3	0.000	0.000	1.900
C4	0.000	0.000	-1.900
H5	0.000	0.000	2.961
H6	0.000	0.000	-2.961

	C1	C2	C3	C4	H5	H6
C1		1.3680	1.2160	2.5840	2.2774	3.6454
C2	1.3680		2.5840	1.2160	3.6454	2.2774
C3	1.2160	2.5840		3.8001	1.0614	4.8615
C4	2.5840	1.2160	3.8001		4.8615	1.0614
H5	2.2774	3.6454	1.0614	4.8615		5.9229
H6	3.6454	2.2774	4.8615	1.0614	5.9229

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: B2PLYP=FULL/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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All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: B2PLYP=FULL/3-21G*

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)