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	hartrees
Energy at 0K	-76.582425
Energy at 298.15K	-76.582378
HF Energy	-76.393162
Nuclear repulsion energy	24.498450

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)	Raman Act (Å⁴/u)	Dep P	Dep U
1	Σ_g	3534	3350	0.00	66.04	0.21	0.34
2	Σ_g	1971	1868	0.00	24.58	0.29	0.45
3	Σ_u	3438	3260	72.84	0.00	0.00	0.00
4	Π_g	507	481	0.00	1.25	0.75	0.86
4	Π_g	507	481	0.00	1.25	0.75	0.86
5	Π_u	741	703	99.06	0.00	0.00	0.00
5	Π_u	741	703	99.06	0.00	0.00	0.00

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.611
C2	0.000	0.000	-0.611
H3	0.000	0.000	1.675
H4	0.000	0.000	-1.675

	C1	C2	H3	H4
C1		1.2215	1.0643	2.2858
C2	1.2215		2.2858	1.0643
H3	1.0643	2.2858		3.3500
H4	2.2858	1.0643	3.3500

All results from a given calculation for C₂H₂ (Acetylene)

using model chemistry: MP2=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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HF vs MP2 Bad vib. Calc. vs exp. 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All results from a given calculation for C2H2 (Acetylene)

using model chemistry: MP2=FULL/3-21G*

States and conformations

All results from a given calculation for C₂H₂ (Acetylene)