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State	Conformation	minimum conformation	conformer description	state description
1	1	no	D*H	¹Σ_g
1	2	yes	C2H	¹A_G

	hartrees
Energy at 0K	-152.024452
Energy at 298.15K
HF Energy	-151.650066
Nuclear repulsion energy	76.396694

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3438	3343	0.00
2	Σ_g	2278	2215	0.00
3	Σ_g	866	842	0.00
4	Σ_u	3438	3342	103.23
5	Σ_u	2082	2025	0.05
6	Π_g	593	576	0.00
6	Π_g	593	576	0.00
7	Π_g	666i	647i	0.00
7	Π_g	666i	647i	0.00
8	Π_u	565	549	100.21
8	Π_u	565	549	100.21
9	Π_u	138	134	1.52
9	Π_u	138	134	1.52

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	0.695
C2	0.000	0.000	-0.695
C3	0.000	0.000	1.913
C4	0.000	0.000	-1.913
H5	0.000	0.000	2.982
H6	0.000	0.000	-2.982

	C1	C2	C3	C4	H5	H6
C1		1.3906	1.2181	2.6087	2.2864	3.6769
C2	1.3906		2.6087	1.2181	3.6769	2.2864
C3	1.2181	2.6087		3.8268	1.0683	4.8950
C4	2.6087	1.2181	3.8268		4.8950	1.0683
H5	2.2864	3.6769	1.0683	4.8950		5.9633
H6	3.6769	2.2864	4.8950	1.0683	5.9633

All results from a given calculation for C₄H₂ (Diacetylene)

using model chemistry: CCD/3-21G

States and conformations

Conformer 1 (D*H)

Conformer 2 (C2H)

	Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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You are here: Calculated > Energy > Optimized > Energy

	hartrees
Energy at 0K	-152.024928
Energy at 298.15K	-152.023858
HF Energy	-151.648791
Nuclear repulsion energy	76.433336

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3444	3349	0.00
2	A_g	2280	2216	0.00
3	A_g	875	851	0.00
4	A_g	736	716	0.00
5	A_g	573	558	0.00
6	A_u	631	613	94.23
7	A_u	189	184	4.26
8	B_g	630	613	0.00
9	B_u	3444	3349	100.90
10	B_u	2086	2029	0.04
11	B_u	675	656	90.35
12	B_u	205	199	6.48

Atom	x (Å)	y (Å)
C1	-0.033	0.694
C2	0.033	-0.694
C3	0.033	1.911
C4	-0.033	-1.911
H5	0.014	2.978
H6	-0.014	-2.978

	C1	C2	C3	C4	H5	H6
C1		1.3900	1.2183	2.6050	2.2846	3.6726
C2	1.3900		2.6050	1.2183	3.6726	2.2846
C3	1.2183	2.6050		3.8220	1.0678	4.8893
C4	2.6050	1.2183	3.8220		4.8893	1.0678
H5	2.2846	3.6726	1.0678	4.8893		5.9567
H6	3.6726	2.2846	4.8893	1.0678	5.9567

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

atom1	atom2	atom3	angle		atom1	atom2	atom3	angle
C1	C2	C4	174.193		C1	C3	H5	175.882
C2	C1	C3	174.193		C2	C4	H6	175.882

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: CCD/3-21G

States and conformations

Conformer 1 (D*H)

Conformer 2 (C2H)

All results from a given calculation for C₄H₂ (Diacetylene)