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	hartrees
Energy at 0K	-153.036064
Energy at 298.15K	-153.033820
HF Energy	-152.492530
Nuclear repulsion energy	76.343021

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)
1	Σ_g	3467	3326
2	Σ_g	2249	2157
3	Σ_g	896	860
4	Σ_u	3468	3327
5	Σ_u	2065	1981
6	Π_g	581	557
6	Π_g	581	557
7	Π_g	102	98
7	Π_g	102	98
8	Π_u	440	422
8	Π_u	440	422
9	Π_u	216	207
9	Π_u	216	207

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.692
C2	0.000	0.000	-0.692
C3	0.000	0.000	1.914
C4	0.000	0.000	-1.914
H5	0.000	0.000	2.985
H6	0.000	0.000	-2.985

	C1	C2	C3	C4	H5	H6
C1		1.3844	1.2221	2.6065	2.2930	3.6774
C2	1.3844		2.6065	1.2221	3.6774	2.2930
C3	1.2221	2.6065		3.8286	1.0709	4.8995
C4	2.6065	1.2221	3.8286		4.8995	1.0709
H5	2.2930	3.6774	1.0709	4.8995		5.9704
H6	3.6774	2.2930	4.8995	1.0709	5.9704

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(T)/6-31G*

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(T)/6-31G*

States and conformations

All results from a given calculation for C₄H₂ (Diacetylene)