From the Selection list, choose the domains (from its parent feature) on which the surface reaction rate is defined.
 
    Select a surface reaction rate (SI unit: kg/(m2·s)) for species 
i from 
Rsi list. Enter a reaction rate expression when 
User defined is selected from the list. Alternatively, if surface reaction rate expressions have been defined in a Chemistry interface, they can be chosen from the list.
 
    Select a surface reaction rate (SI unit: kg/(m2·s)) for adsorbed species cads_
i from 
Rscads_i list. If 
User defined is selected from the list, enter a surface reaction rate expression. Alternatively, if surface reaction rate expressions have been defined in a Chemistry interface, they can be chosen from the list.
 
    Select a surface reaction rate (SI unit: kg/(m2·s)) from 
column Surface reaction rate for a surface species which is defined in the parent feature. With 
User defined being selected, the table cell at the same row under column 
Surface rate expression (kg/(m2·s)) is editable (otherwise it is read-only), and enter a surface reaction rate expression. Alternatively, if surface reaction rate expressions have been defined in a Chemistry interface, they can be chosen from the list under column 
Surface reaction rate.