Tropospheric Chemistry Modelling Group

Estimation by EVAPORATION

The vapour pressure of an organic compound is one of the main factors controlling its equilibrium partitioning between the gas and condensed (aerosol) phases.

Here we present the method EVAPORATION of Compernolle et al. (1), which calculates the vapour pressure of an organic molecule from molecular structure. Functional groups within its scope are: aldehyde, ketone, ether, ester, alcohol, nitrate, acid, peroxide, hydroperoxide, peracid and peroxy acyl nitrate. Aromatics are not treated.

Please specify the molecular structure by a SMILES string, and the temperature (in Kelvin). With e.g. the online program Marvin one can generate a SMILES from a molecular drawing.

The empirical factor for functionalized diacids was introduced to accommodate data like those of Booth et al., (Atmos. Chem. Phys. 2010) . However, more recent data of Huisman et al., (Atmos. Chem. Phys. 2013) are in clear disagreement with such a factor. Therefore, the user can choose to turn it off.

Temperature (K):


Use empirical factor for functionalized diacids:




  • Compernolle, S., K. Ceulemans, and J.-F. Müller, EVAPORATION: a new vapor pressure estimation method for organic molecules including non-additivity and intramolecular interactions, Atmos. Chem. Phys., 19431-9450, 2011. [abstract][pdf]
  • Clarification about EVAPORATION. [pdf]

Bug corrections

  • 11 May 2014. Concerning descriptor 19. Number of functional groups in alpha of alcohol was not always counted correctly. Thanks to Dr. William Carter for spotting this bug.
  • 11 May 2014. Concerning descriptor 12. 'Ester in ring' was sometimes not counted for this descriptor. Thanks to Dr. William Carter for spotting this bug.