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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	-151.980152
Energy at 298.15K
HF Energy	-151.652475
Nuclear repulsion energy	76.914136

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	Σ_g	3516	3285	0.00
2	Σ_g	2366	2210	0.00
3	Σ_g	893	835	0.00
4	Σ_u	3515	3284	129.78
5	Σ_u	2158	2017	0.03
6	Π_g	655	612	0.00
6	Π_g	655	612	0.00
7	Π_g	570i	532i	0.00
7	Π_g	570i	532i	0.00
8	Π_u	656	613	106.16
8	Π_u	656	613	106.16
9	Π_u	170	158	3.83
9	Π_u	170	158	3.83

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	1.900
C4	0.000	0.000	-1.900
H5	0.000	0.000	2.963
H6	0.000	0.000	-2.963

	C1	C2	C3	C4	H5	H6
C1		1.3842	1.2082	2.5924	2.2706	3.6548
C2	1.3842		2.5924	1.2082	3.6548	2.2706
C3	1.2082	2.5924		3.8006	1.0625	4.8630
C4	2.5924	1.2082	3.8006		4.8630	1.0625
H5	2.2706	3.6548	1.0625	4.8630		5.9255
H6	3.6548	2.2706	4.8630	1.0625	5.9255

All results from a given calculation for C₄H₂ (Diacetylene)

using model chemistry: CISD/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	-151.980392
Energy at 298.15K	-151.979433
HF Energy	-151.651678
Nuclear repulsion energy	76.940312

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3520	3289	0.00
2	A_g	2367	2212	0.00
3	A_g	900	841	0.00
4	A_g	757	707	0.00
5	A_g	566	529	0.00
6	A_u	699	653	102.33
7	A_u	200	187	5.86
8	B_g	685	640	0.00
9	B_u	3519	3288	128.06
10	B_u	2161	2020	0.03
11	B_u	726	678	99.27
12	B_u	210	196	7.31

Atom	x (Å)	y (Å)
C1	-0.026	0.691
C2	0.026	-0.691
C3	0.026	1.899
C4	-0.026	-1.899
H5	0.018	2.961
H6	-0.018	-2.961

	C1	C2	C3	C4	H5	H6
C1		1.3838	1.2082	2.5899	2.2696	3.6520
C2	1.3838		2.5899	1.2082	3.6520	2.2696
C3	1.2082	2.5899		3.7974	1.0621	4.8593
C4	2.5899	1.2082	3.7974		4.8593	1.0621
H5	2.2696	3.6520	1.0621	4.8593		5.9213
H6	3.6520	2.2696	4.8593	1.0621	5.9213

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	175.354		C1	C3	H5	177.067
C2	C1	C3	175.354		C2	C4	H6	177.067

All results from a given calculation for C4H2 (Diacetylene)

using model chemistry: CISD/3-21G*

States and conformations

Conformer 1 (D*H)

Conformer 2 (C2H)

All results from a given calculation for C₄H₂ (Diacetylene)