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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	-151.976911
Energy at 298.15K
HF Energy	-151.652650
Nuclear repulsion energy	76.954897

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3521	3280	0.00
2	Σ_g	2373	2211	0.00
3	Σ_g	895	834	0.00
4	Σ_u	3520	3279	127.54
5	Σ_u	2167	2019	0.02
6	Π_g	656	611	0.00
6	Π_g	656	611	0.00
7	Π_g	576i	537i	0.00
7	Π_g	576i	537i	0.00
8	Π_u	658	613	106.99
8	Π_u	658	613	106.99
9	Π_u	170	158	3.80
9	Π_u	170	158	3.80

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	1.899
C4	0.000	0.000	-1.899
H5	0.000	0.000	2.961
H6	0.000	0.000	-2.961

	C1	C2	C3	C4	H5	H6
C1		1.3842	1.2071	2.5913	2.2693	3.6535
C2	1.3842		2.5913	1.2071	3.6535	2.2693
C3	1.2071	2.5913		3.7984	1.0622	4.8607
C4	2.5913	1.2071	3.7984		4.8607	1.0622
H5	2.2693	3.6535	1.0622	4.8607		5.9229
H6	3.6535	2.2693	4.8607	1.0622	5.9229

All results from a given calculation for C₄H₂ (Diacetylene)

using model chemistry: CID/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	-151.977157
Energy at 298.15K	-151.976216
HF Energy	-151.651847
Nuclear repulsion energy	76.980695

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3525	3284	0.00
2	A_g	2374	2212	0.00
3	A_g	902	840	0.00
4	A_g	762	710	0.00
5	A_g	569	530	0.00
6	A_u	701	653	103.01
7	A_u	201	187	5.84
8	B_g	687	640	0.00
9	B_u	3525	3283	125.88
10	B_u	2170	2022	0.02
11	B_u	729	679	99.78
12	B_u	211	196	7.33

Atom	x (Å)	y (Å)
C1	-0.026	0.691
C2	0.026	-0.691
C3	0.026	1.897
C4	-0.026	-1.897
H5	0.018	2.959
H6	-0.018	-2.959

	C1	C2	C3	C4	H5	H6
C1		1.3839	1.2072	2.5889	2.2683	3.6507
C2	1.3839		2.5889	1.2072	3.6507	2.2683
C3	1.2072	2.5889		3.7953	1.0619	4.8570
C4	2.5889	1.2072	3.7953		4.8570	1.0619
H5	2.2683	3.6507	1.0619	4.8570		5.9187
H6	3.6507	2.2683	4.8570	1.0619	5.9187

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	175.339		C1	C3	H5	177.077
C2	C1	C3	175.339		C2	C4	H6	177.077

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: CID/3-21G

States and conformations

Conformer 1 (D*H)

Conformer 2 (C2H)

All results from a given calculation for C₄H₂ (Diacetylene)