Skip to contents

The photolysis dataset contains numerical values for describing the photolytic degradation pathways of 25 compounds of relevance in atmospheric chemistry. Many volatile organic compounds (VOCs) are emitted in substantial quantities from both biogenic and anthropogenic sources, and they can have a major influence on the chemistry of the lower atmosphere. A portion of these can be transformed into other VOCs via the energy provided from light.

In order to realistically predict the composition of the atmosphere and how it evolves over time, we need accurate estimates of photolysis rates. The data provided here in photolysis allows for computations of photolysis rates (J, having units of s^-1) as a function of the solar zenith angle (SZA). Having such values is essential when deploying atmospheric chemistry models.

Usage

photolysis

Format

A tibble with 34 rows and 10 variables:

compd_name

The name of the primary compound undergoing photolysis.

cmpd_formula

The chemical formula of the compound.

products

A product pathway for the photolysis of the compound.

type

The type of organic compound undergoing photolysis.

l, m, n

The parameter values given in the l, m, and n columns can be used to calculate the photolysis rate (J) as a function of the solar zenith angle (X, in radians) through the expression: J = l * cos(X)^m * exp(-n * sec(X)).

quantum_yield

In the context of photolysis reactions, this is the efficiency of a given photolytic reaction. In other words, it's the number of product molecules formed over the number of photons absorbed.

wavelength_nm, sigma_298_cm2

The wavelength_nm and sigma_298_cm2 columns provide photoabsorption data for the compound undergoing photolysis. The values in wavelength_nm provide the wavelength of light in nanometer units; the sigma_298_cm2 values are paired with the wavelength_nm values and they are in units of cm^2 molecule^-1.

Examples

Here is a glimpse at the data available in photolysis.

dplyr::glimpse(photolysis)
#> Rows: 34
#> Columns: 10
#> $ cmpd_name     <chr> "ozone", "ozone", "hydrogen peroxide", "nitrogen dioxide~
#> $ cmpd_formula  <chr> "O3", "O3", "H2O2", "NO2", "NO3", "NO3", "HONO", "HNO3",~
#> $ products      <chr> "-> O(^1D) + O2", "-> O(^3P) + O2", "-> OH + OH", "-> NO~
#> $ type          <chr> "inorganic reactions", "inorganic reactions", "inorganic~
#> $ l             <dbl> 6.073e-05, 4.775e-04, 1.041e-05, 1.165e-02, 2.485e-02, 1~
#> $ m             <dbl> 1.743, 0.298, 0.723, 0.244, 0.168, 0.155, 0.261, 1.230, ~
#> $ n             <dbl> 0.474, 0.080, 0.279, 0.267, 0.108, 0.125, 0.288, 0.307, ~
#> $ quantum_yield <dbl> NA, NA, 1.000, NA, 1.000, 1.000, 1.000, 1.000, NA, NA, N~
#> $ wavelength_nm <chr> "290,291,292,293,294,295,296,297,298,299,300,301,302,303~
#> $ sigma_298_cm2 <chr> "1.43E-18,1.27E-18,1.11E-18,9.94E-19,8.68E-19,7.69E-19,6~

Dataset ID and Badge

DATA-15

This image of that of a dataset badge.

Dataset Introduced

In Development