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All results from a given calculation for C4H2O3 (Maleic Anhydride)

using model chemistry: HF/3-21G*

19 10 17 12 22

States and conformations

State Conformation minimum conformation conformer description state description
1 1 yes C2V 1A1
Energy calculated at HF/3-21G*
 hartrees
Energy at 0K-375.103514
Energy at 298.15K-375.107165
HF Energy-375.103514
Nuclear repulsion energy275.373482
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 HF/3-21G*
Mode Number Symmetry Frequency
(cm-1)
Scaled Frequency
(cm-1)
IR Intensities
(km mol-1)
Raman Act
4/u)
Dep P Dep U
1 A1 3479 3140 3.02      
2 A1 2099 1895 65.70      
3 A1 1807 1631 0.86      
4 A1 1321 1192 155.49      
5 A1 1189 1073 74.77      
6 A1 897 810 3.13      
7 A1 694 627 0.16      
8 A1 427 386 16.22      
9 A2 1175 1060 0.00      
10 A2 846 763 0.00      
11 A2 322 290 0.00      
12 B1 1006 908 158.73      
13 B1 720 650 5.61      
14 B1 186 168 1.63      
15 B2 3455 3118 4.25      
16 B2 2012 1816 657.00      
17 B2 1465 1322 7.27      
18 B2 1135 1024 95.40      
19 B2 1002 904 75.65      
20 B2 782 706 20.12      
21 B2 590 532 2.53      

Unscaled Zero Point Vibrational Energy (zpe) 13302.9 cm-1
Scaled (by 0.9026) Zero Point Vibrational Energy (zpe) 12007.2 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 HF/3-21G*
ABC
0.23017 0.08180 0.06035

See section I.F.4 to change rotational constant units
Geometric Data calculated at HF/3-21G*

Point Group is C2v

Cartesians (Å)
Atom x (Å) y (Å) z (Å)
O1 0.000 0.000 0.958
C2 0.000 1.141 0.163
C3 0.000 -1.141 0.163
O4 0.000 2.243 0.601
O5 0.000 -2.243 0.601
C6 0.000 0.658 -1.255
C7 0.000 -0.658 -1.255
H8 0.000 1.329 -2.082
H9 0.000 -1.329 -2.082

Atom - Atom Distances (Å)
  O1 C2 C3 O4 O5 C6 C7 H8 H9
O11.39031.39032.27102.27102.30892.30893.31763.3176
C21.39032.28111.18613.41161.49802.29032.25253.3375
C31.39032.28113.41161.18612.29031.49803.33752.2525
O42.27101.18613.41164.48562.44073.44372.83384.4673
O52.27103.41161.18614.48563.44372.44074.46732.8338
C62.30891.49802.29032.44073.44371.31591.06492.1524
C72.30892.29031.49803.44372.44071.31592.15241.0649
H83.31762.25253.33752.83384.46731.06492.15242.6589
H93.31763.33752.25254.46732.83382.15241.06492.6589

picture of Maleic Anhydride state 1 conformation 1
More geometry information
Calculated Bond Angles
atom1 atom2 atom3 angle atom1 atom2 atom3 angle
O1 C2 O4 123.449 O1 C2 C6 106.084
O1 C3 O5 123.449 O1 C3 C7 106.084
C2 O1 C3 110.241 C2 C6 C7 108.795
C2 C6 H8 122.110 C3 C7 C6 108.795
C3 C7 H9 122.110 O4 C2 C6 130.467
O5 C3 C7 130.467 C6 C7 H9 129.094
C7 C6 H8 129.094
Electronic energy levels
Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at HF/3-21G* Charges (e)
Number Element Mulliken CHELPG AIM ESP
1 O -0.706      
2 C 0.892      
3 C 0.892      
4 O -0.544      
5 O -0.544      
6 C -0.307      
7 C -0.307      
8 H 0.312      
9 H 0.312      


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 -4.941 4.941
CHELPG        
AIM        
ESP        


Electric Quadrupole moment
Quadrupole components in D Å
Primitive
 xyz
x -37.849 0.000 0.000
y 0.000 -49.530 0.000
z 0.000 0.000 -37.300
Traceless
 xyz
x 5.566 0.000 0.000
y 0.000 -11.955 0.000
z 0.000 0.000 6.389
Polar
3z2-r212.778
x2-y211.680
xy0.000
xz0.000
yz0.000


Polarizabilities
Components of the polarizability tensor.
Units are Å3 (Angstrom cubed)
Change units.
  x y z
x 2.025 0.000 0.000
y 0.000 9.795 0.000
z 0.000 0.000 4.843


<r2> (average value of r2) Å2
<r2> 171.790
(<r2>)1/2 13.107