National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 19April 2018
NIST Standard Reference Database 101
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
VIInput and output files
VIITutorials and Units
VIIILinks to other sites
XOlder CCCBDB versions
XIII Vibrations
XIVReaction data
XVEntropy data
XVIBibliographic data
XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers

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All results from a given calculation for HNO2 (Nitrous acid)

using model chemistry: HF/cc-pVTZ

States and conformations

State Conformation minimum conformation conformer description state description
1 1 yes CS 1A'
Energy calculated at HF/cc-pVTZ
Energy at 0K-204.727486
Energy at 298.15K-204.723359
Nuclear repulsion energy72.405653
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/cc-pVTZ
Mode Number Symmetry Frequency (cm-1) Scaled Frequency (cm-1) IR Intensities (km mol-1)
1 A' 4132 3761 132.24
2 A' 2020 1838 170.77
3 A' 1497 1362 251.58
4 A' 1071 975 244.80
5 A' 796 724 25.08
6 A" 593 539 119.15

Unscaled Zero Point Vibrational Energy (zpe) 5054.0 cm-1
Scaled (by 0.9101) Zero Point Vibrational Energy (zpe) 4599.7 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/cc-pVTZ
3.47463 0.45340 0.40107

See section I.F.4 to change rotational constant units
Geometric Data calculated at HF/cc-pVTZ

Point Group is Cs

Cartesians (Å)
Atom x (Å) y (Å) z (Å)
H1 1.725 -0.142 0.000
O2 0.868 -0.538 0.000
N3 0.000 0.489 0.000
O4 -1.084 0.128 0.000

Atom - Atom Distances (Å)

  H1 O2 N3 O4

picture of Nitrous acid
More geometry information

Calculated Bond Angles

atom1 atom2 atom3 angle atom1 atom2 atom3 angle
H1 O2 N3 105.385 O2 N3 O4 111.776
Electronic energy levels

Electronic state

Charges, Dipole, Quadrupole and Polarizability

Charges from optimized geometry at HF/cc-pVTZ Charges (e)

Number Element Mulliken CHELPG AIM ESP
1 H 0.223 0.356 0.664 0.357
2 O -0.248 -0.313 -0.876 -0.314
3 N 0.200 0.085 0.807 0.081
4 O -0.175 -0.128 -0.597 -0.124

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

  x y z Total
  -0.308 -1.532 0.000 1.562
AIM -0.979 -1.052 0.000 1.437

Electric Quadrupole moment
Quadrupole components in D Å

x -13.389 0.620 0.000
y 0.620 -18.075 0.000
z 0.000 0.000 -15.699
x 3.499 0.620 0.000
y 0.620 -3.531 0.000
z 0.000 0.000 0.033

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

  x y z
x 3.482 -0.238 0.000
y -0.238 1.842 0.000
z 0.000 0.000 1.388

<r2> (averge value of r2) Å2

<r2> 32.357
(<r2>)1/2 5.688