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	hartrees
Energy at 0K	-153.027655
Energy at 298.15K	-153.026766
HF Energy	-152.504785
Nuclear repulsion energy	75.875031

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3476	3335	0.00
2	Σ_g	2275	2183	0.00
3	Σ_g	889	853	0.00
4	Σ_u	3475	3334	156.23
5	Σ_u	2080	1996	0.01
6	Π_g	633	608	0.00
6	Π_g	633	608	0.00
7	Π_g	496	476	0.00
7	Π_g	496	476	0.00
8	Π_u	629	604	75.50
8	Π_u	629	604	75.50
9	Π_u	227	217	5.17
9	Π_u	227	217	5.17

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.699
C2	0.000	0.000	-0.699
C3	0.000	0.000	1.926
C4	0.000	0.000	-1.926
H5	0.000	0.000	3.004
H6	0.000	0.000	-3.004

	C1	C2	C3	C4	H5	H6
C1		1.3988	1.2267	2.6255	2.3044	3.7032
C2	1.3988		2.6255	1.2267	3.7032	2.3044
C3	1.2267	2.6255		3.8522	1.0777	4.9299
C4	2.6255	1.2267	3.8522		4.9299	1.0777
H5	2.3044	3.7032	1.0777	4.9299		6.0076
H6	3.7032	2.3044	4.9299	1.0777	6.0076

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: QCISD/cc-pVDZ

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: QCISD/cc-pVDZ

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)