CCCBDB calculation results Page

State	Conformation	minimum conformation	conformer description	state description
1	1	no	C2H	¹A_g
1	2	yes	C2	¹A
1	3	no	CI	¹A_g

Conformer 1 (C2H)

Jump to S1C2 S1C3

Energy calculated at PBEPBE/3-21G

	hartrees
Energy at 0K	-304.426567
Energy at 298.15K
Nuclear repulsion energy	223.798376

The energy at 298.15K was derived from the energy at 0K and an integrated heat capacity that used the calculated vibrational frequencies.

Vibrational Frequencies calculated at PBEPBE/3-21G

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3115	3087	0.00
2	A_g	2999	2971	0.00
3	A_g	1679	1664	0.00
4	A_g	1460	1447	0.00
5	A_g	1385	1373	0.00
6	A_g	1212	1201	0.00
7	A_g	986	977	0.00
8	A_g	648	643	0.00
9	A_g	522	518	0.00
10	A_g	366	362	0.00
11	A_u	3055	3028	1.94
12	A_u	1475	1462	30.80
13	A_u	964	955	11.45
14	A_u	370	367	0.48
15	A_u	117	116	2.66
16	A_u	46i	45i	6.95
17	B_g	3056	3028	0.00
18	B_g	1482	1469	0.00
19	B_g	1070	1060	0.00
20	B_g	658	652	0.00
21	B_g	28i	28i	0.00
22	B_u	3115	3087	12.54
23	B_u	2999	2971	0.34
24	B_u	1680	1665	105.38
25	B_u	1463	1450	34.31
26	B_u	1384	1372	113.93
27	B_u	1116	1106	96.00
28	B_u	885	877	27.64
29	B_u	514	509	24.42
30	B_u	244	241	18.71

Unscaled Zero Point Vibrational Energy (zpe) 19972.5 cm^-1
Scaled (by 0.9909) Zero Point Vibrational Energy (zpe) 19790.8 cm^-1
See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.

Rotational Constants (cm^-1) from geometry optimized at PBEPBE/3-21G

A	B	C
0.16648	0.11487	0.06974

See section I.F.4 to change rotational constant units

Geometric Data calculated at PBEPBE/3-21G

Point Group is C_2h

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
C1	-0.084	0.770	0.000
C2	0.084	-0.770	0.000
C3	1.224	1.530	0.000
C4	-1.224	-1.530	0.000
O5	-1.224	1.271	0.000
O6	1.224	-1.271	0.000
H7	1.037	2.613	0.000
H8	-1.037	-2.613	0.000
H9	1.821	1.241	0.884
H10	1.821	1.241	-0.884
H11	-1.821	-1.241	0.884
H12	-1.821	-1.241	-0.884

Atom - Atom Distances (Å)

	C1	C2	C3	C4	O5	O6	H7	H8	H9	H10	H11	H12
C1		1.5500	1.5131	2.5678	1.2453	2.4246	2.1571	3.5153	2.1523	2.1523	2.8008	2.8008
C2	1.5500		2.5678	1.5131	2.4246	1.2453	3.5153	2.1571	2.8008	2.8008	2.1523	2.1523
C3	1.5131	2.5678		3.9196	2.4625	2.8010	1.0990	4.7205	1.1049	1.1049	4.2115	4.2115
C4	2.5678	1.5131	3.9196		2.8010	2.4625	4.7205	1.0990	4.2115	4.2115	1.1049	1.1049
O5	1.2453	2.4246	2.4625	2.8010		3.5293	2.6301	3.8885	3.1714	3.1714	2.7288	2.7288
O6	2.4246	1.2453	2.8010	2.4625	3.5293		3.8885	2.6301	2.7288	2.7288	3.1714	3.1714
H7	2.1571	3.5153	1.0990	4.7205	2.6301	3.8885		5.6230	1.8107	1.8107	4.8792	4.8792
H8	3.5153	2.1571	4.7205	1.0990	3.8885	2.6301	5.6230		4.8792	4.8792	1.8107	1.8107
H9	2.1523	2.8008	1.1049	4.2115	3.1714	2.7288	1.8107	4.8792		1.7674	4.4077	4.7489
H10	2.1523	2.8008	1.1049	4.2115	3.1714	2.7288	1.8107	4.8792	1.7674		4.7489	4.4077
H11	2.8008	2.1523	4.2115	1.1049	2.7288	3.1714	4.8792	1.8107	4.4077	4.7489		1.7674
H12	2.8008	2.1523	4.2115	1.1049	2.7288	3.1714	4.8792	1.8107	4.7489	4.4077	1.7674

picture of 2,3-Butanedione state 1 conformation 1

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	113.917	C1	C2	O6	119.918
C1	C3	H7	110.339	C1	C3	H9	109.612
C1	C3	H10	109.612	C2	C1	C3	113.917
C2	C1	O5	119.918	C2	C4	H8	110.339
C2	C4	H11	109.612	C2	C4	H12	109.612
C3	C1	O5	126.165	C4	C2	O6	126.165
H7	C3	H9	110.484	H7	C3	H10	110.484
H8	C4	H11	110.484	H8	C4	H12	110.484
H9	C3	H10	106.224	H11	C4	H12	106.224

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at PBEPBE/3-21G Charges (e)

Number	Element	Mulliken
1	C	0.330
2	C	0.330
3	C	-0.663
4	C	-0.663
5	O	-0.398
6	O	-0.398
7	H	0.234
8	H	0.234
9	H	0.248
10	H	0.248
11	H	0.248
12	H	0.248

Electric dipole moments
Electric dipole components in Debye
(What's a Debye? See section VII.A.3)

	x	y	z	Total
	0.000	0.000	0.000	0.000
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-37.668	6.692	0.000
y	6.692	-36.481	0.000
z	0.000	0.000	-33.661

Traceless
	x	y	z
x	-2.597	6.692	0.000
y	6.692	-0.817	0.000
z	0.000	0.000	3.414

Polar
3z²-r²	6.828
x²-y²	-1.187
xy	6.692
xz	0.000
yz	0.000

Polarizabilities
Components of the polarizability tensor.
Units are Å³ (Angstrom cubed)
Change units.

	x	y	z
x	7.739	0.106	0.000
y	0.106	6.875	0.000
z	0.000	0.000	4.222

<r²> (average value of r²) Å²

<r²>	163.928
(<r²>)^1/2	12.803

Conformer 2 (C2)

Jump to S1C1 S1C3

Energy calculated at PBEPBE/3-21G

	hartrees
Energy at 0K	-304.426954
Energy at 298.15K	-304.432992
Nuclear repulsion energy	223.657746

The energy at 298.15K was derived from the energy at 0K and an integrated heat capacity that used the calculated vibrational frequencies.

Vibrational Frequencies calculated at PBEPBE/3-21G

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A	3119	3090	0.27
2	A	3063	3035	2.64
3	A	2985	2958	0.71
4	A	1668	1653	0.47
5	A	1488	1474	4.11
6	A	1466	1453	26.40
7	A	1377	1365	1.43
8	A	1193	1182	0.95
9	A	998	988	1.20
10	A	963	954	13.99
11	A	639	633	0.23
12	A	533	528	0.22
13	A	389	386	0.82
14	A	368	365	0.88
15	A	111	110	6.07
16	A	65	64	2.33
17	B	3119	3090	1.32
18	B	3062	3034	6.85
19	B	2985	2958	1.05
20	B	1677	1661	93.09
21	B	1488	1474	28.87
22	B	1471	1457	16.69
23	B	1376	1364	141.26
24	B	1112	1102	123.17
25	B	1073	1064	3.82
26	B	912	904	17.52
27	B	652	646	0.21
28	B	511	507	16.49
29	B	280	277	20.79
30	B	71	70	1.47

Unscaled Zero Point Vibrational Energy (zpe) 20105.9 cm^-1
Scaled (by 0.9909) Zero Point Vibrational Energy (zpe) 19922.9 cm^-1
See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.

Rotational Constants (cm^-1) from geometry optimized at PBEPBE/3-21G

A	B	C
0.16659	0.11393	0.06959

See section I.F.4 to change rotational constant units

Geometric Data calculated at PBEPBE/3-21G

Point Group is C₂

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
C1	-0.084	0.774	-0.019
C2	0.084	-0.774	-0.019
C3	1.223	1.531	0.059
C4	-1.223	-1.531	0.059
O5	-1.223	1.277	-0.070
O6	1.223	-1.277	-0.070
H7	1.159	2.474	-0.505
H8	-1.159	-2.474	-0.505
H9	1.423	1.784	1.119
H10	2.043	0.889	-0.293
H11	-1.423	-1.784	1.119
H12	-2.043	-0.889	-0.293

Atom - Atom Distances (Å)

	C1	C2	C3	C4	O5	O6	H7	H8	H9	H10	H11	H12
C1		1.5564	1.5128	2.5717	1.2461	2.4323	2.1616	3.4551	2.1422	2.1484	3.1034	2.5841
C2	1.5564		2.5717	1.5128	2.4323	1.2461	3.4551	2.1616	3.1034	2.5841	2.1422	2.1484
C3	1.5128	2.5717		3.9189	2.4627	2.8106	1.1008	4.6936	1.1083	1.0997	4.3723	4.0803
C4	2.5717	1.5128	3.9189		2.8106	2.4627	4.6936	1.1008	4.3723	4.0803	1.1083	1.0997
O5	1.2461	2.4323	2.4627	2.8106		3.5362	2.7010	3.7765	2.9453	3.2971	3.2902	2.3265
O6	2.4323	1.2461	2.8106	2.4627	3.5362		3.7765	2.7010	3.2902	2.3265	2.9453	3.2971
H7	2.1616	3.4551	1.1008	4.6936	2.7010	3.7765		5.4638	1.7843	1.8276	5.2381	4.6484
H8	3.4551	2.1616	4.6936	1.1008	3.7765	2.7010	5.4638		5.2381	4.6484	1.7843	1.8276
H9	2.1422	3.1034	1.1083	4.3723	2.9453	3.2902	1.7843	5.2381		1.7838	4.5647	4.5998
H10	2.1484	2.5841	1.0997	4.0803	3.2971	2.3265	1.8276	4.6484	1.7838		4.5998	4.4568
H11	3.1034	2.1422	4.3723	1.1083	3.2902	2.9453	5.2381	1.7843	4.5647	4.5998		1.7838
H12	2.5841	2.1484	4.0803	1.0997	2.3265	3.2971	4.6484	1.8276	4.5998	4.4568	1.7838

picture of 2,3-Butanedione state 1 conformation 2

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	113.830	C1	C2	O6	120.026
C1	C3	H7	110.606	C1	C3	H9	108.648
C1	C3	H10	109.631	C2	C1	C3	113.830
C2	C1	O5	120.026	C2	C4	H8	110.606
C2	C4	H11	108.648	C2	C4	H12	109.631
C3	C1	O5	126.142	C4	C2	O6	126.142
H7	C3	H9	107.744	H7	C3	H10	112.311
H8	C4	H11	107.744	H8	C4	H12	112.311
H9	C3	H10	107.779	H11	C4	H12	107.779

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at PBEPBE/3-21G Charges (e)

Number	Element	Mulliken
1	C	0.339
2	C	0.339
3	C	-0.676
4	C	-0.676
5	O	-0.400
6	O	-0.400
7	H	0.242
8	H	0.242
9	H	0.250
10	H	0.245
11	H	0.250
12	H	0.245

Electric dipole moments
Electric dipole components in Debye
(What's a Debye? See section VII.A.3)

	x	y	z	Total
	0.000	0.000	0.453	0.453
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-38.211	6.729	0.000
y	6.729	-35.764	0.000
z	0.000	0.000	-33.657

Traceless
	x	y	z
x	-3.500	6.729	0.000
y	6.729	0.170	0.000
z	0.000	0.000	3.330

Polar
3z²-r²	6.661
x²-y²	-2.446
xy	6.729
xz	0.000
yz	0.000

Polarizabilities
Components of the polarizability tensor.
Units are Å³ (Angstrom cubed)
Change units.

	x	y	z
x	7.585	0.396	0.000
y	0.396	7.175	0.000
z	0.000	0.000	4.287

<r²> (average value of r²) Å²

<r²>	164.357
(<r²>)^1/2	12.820

Conformer 3 (CI)

Jump to S1C1 S1C2

Energy calculated at PBEPBE/3-21G

	hartrees
Energy at 0K	-304.426820
Energy at 298.15K
Nuclear repulsion energy	223.520123

The energy at 298.15K was derived from the energy at 0K and an integrated heat capacity that used the calculated vibrational frequencies.

Vibrational Frequencies calculated at PBEPBE/3-21G

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3117	3088	0.00
2	A_g	3055	3027	0.00
3	A_g	2996	2969	0.00
4	A_g	1662	1647	0.00
5	A_g	1503	1489	0.00
6	A_g	1475	1462	0.00
7	A_g	1373	1361	0.00
8	A_g	1183	1172	0.00
9	A_g	1077	1067	0.00
10	A_g	999	990	0.00
11	A_g	658	652	0.00
12	A_g	633	627	0.00
13	A_g	536	531	0.00
14	A_g	388	384	0.00
15	A_g	13i	13i	0.00
16	A_u	3116	3088	10.59
17	A_u	3055	3027	3.88
18	A_u	2996	2969	2.83
19	A_u	1676	1661	88.92
20	A_u	1500	1486	24.23
21	A_u	1471	1458	42.06
22	A_u	1373	1360	156.59
23	A_u	1108	1098	145.86
24	A_u	971	962	14.92
25	A_u	924	915	19.24
26	A_u	510	506	13.88
27	A_u	387	383	3.24
28	A_u	290	288	21.86
29	A_u	129	128	3.26
30	A_u	49i	49i	8.20

Unscaled Zero Point Vibrational Energy (zpe) 20048.8 cm^-1
Scaled (by 0.9909) Zero Point Vibrational Energy (zpe) 19866.3 cm^-1
See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.

Rotational Constants (cm^-1) from geometry optimized at PBEPBE/3-21G

A	B	C
0.16694	0.11344	0.06931

See section I.F.4 to change rotational constant units

Geometric Data calculated at PBEPBE/3-21G

Point Group is C_i

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.000	-0.780
C2	0.000	0.000	0.780
C3	1.384	0.000	-1.394
C4	-1.384	0.000	1.394
O5	-1.079	0.000	-1.403
O6	1.079	0.000	1.403
H7	1.505	0.891	-2.036
H8	-1.505	-0.891	2.036
H9	2.138	-0.004	-0.596
H10	1.503	-0.886	-2.043
H11	-2.138	0.004	0.596
H12	-1.503	0.886	2.043

Atom - Atom Distances (Å)

	C1	C2	C3	C4	O5	O6	H7	H8	H9	H10	H11	H12
C1		1.5590	1.5141	2.5768	1.2462	2.4345	2.1540	3.3150	2.1459	2.1542	2.5421	3.3184
C2	1.5590		2.5768	1.5141	2.4345	1.2462	3.3150	2.1540	2.5421	3.3184	2.1459	2.1542
C3	1.5141	2.5768		3.9287	2.4629	2.8135	1.1049	4.5728	1.0986	1.1047	4.0451	4.5753
C4	2.5768	1.5141	3.9287		2.8135	2.4629	4.5728	1.1049	4.0451	4.5753	1.0986	1.1047
O5	1.2462	2.4345	2.4629	2.8135		3.5396	2.8062	3.5782	3.3169	2.8038	2.2616	3.5833
O6	2.4345	1.2462	2.8135	2.4629	3.5396		3.5782	2.8062	2.2616	3.5833	3.3169	2.8038
H7	2.1540	3.3150	1.1049	4.5728	2.8062	3.5782		5.3691	1.8100	1.7768	4.5815	5.0689
H8	3.3150	2.1540	4.5728	1.1049	3.5782	2.8062	5.3691		4.5815	5.0689	1.8100	1.7768
H9	2.1459	2.5421	1.0986	4.0451	3.3169	2.2616	1.8100	4.5815		1.8106	4.4390	4.5838
H10	2.1542	3.3184	1.1047	4.5753	2.8038	3.5833	1.7768	5.0689	1.8106		4.5838	5.3734
H11	2.5421	2.1459	4.0451	1.0986	2.2616	3.3169	4.5815	1.8100	4.4390	4.5838		1.8106
H12	3.3184	2.1542	4.5753	1.1047	3.5833	2.8038	5.0689	1.7768	4.5838	5.3734	1.8106

picture of 2,3-Butanedione state 1 conformation 3

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	113.957	C1	C2	O6	120.005
C1	C3	H7	109.672	C1	C3	H9	109.410
C1	C3	H10	109.696	C2	C1	C3	113.957
C2	C1	O5	120.005	C2	C4	H8	109.672
C2	C4	H11	109.410	C2	C4	H12	109.696
C3	C1	O5	126.037	C4	C2	O6	126.037
H7	C3	H9	110.460	H7	C3	H10	107.052
H8	C4	H11	110.460	H8	C4	H12	107.052
H9	C3	H10	110.520	H11	C4	H12	110.520

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at PBEPBE/3-21G Charges (e)

Number	Element	Mulliken
1	C	0.342
2	C	0.342
3	C	-0.681
4	C	-0.681
5	O	-0.400
6	O	-0.400
7	H	0.248
8	H	0.248
9	H	0.243
10	H	0.248
11	H	0.243
12	H	0.248

Electric dipole moments
Electric dipole components in Debye
(What's a Debye? See section VII.A.3)

	x	y	z	Total
	0.000	0.000	0.000	0.000
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-36.980	0.005	-6.990
y	0.005	-33.631	-0.004
z	-6.990	-0.004	-36.815

Traceless
	x	y	z
x	-1.758	0.005	-6.990
y	0.005	3.267	-0.004
z	-6.990	-0.004	-1.510

Polar
3z²-r²	-3.020
x²-y²	-3.350
xy	0.005
xz	-6.990
yz	-0.004

Polarizabilities
Components of the polarizability tensor.
Units are Å³ (Angstrom cubed)
Change units.

	x	y	z
x	7.628	0.002	-0.480
y	0.002	4.281	0.000
z	-0.480	0.000	7.191

<r²> (average value of r²) Å²

<r²>	164.779
(<r²>)^1/2	12.837

All results from a given calculation for C₄H₆O₂ (2,3-Butanedione)

using model chemistry: PBEPBE/3-21G

States and conformations

Conformer 1 (C2H)

Conformer 2 (C2)

Conformer 3 (CI)

	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 C4H6O2 (2,3-Butanedione)

using model chemistry: PBEPBE/3-21G

States and conformations

Conformer 1 (C2H)

Conformer 2 (C2)

Conformer 3 (CI)

All results from a given calculation for C₄H₆O₂ (2,3-Butanedione)