Table 1 Summary of symbols used in equations
Symbol | Units | Definition |
|---|---|---|
A | molec s kg-1 | Constant from Equation (1.a) |
A surf | m2 | Surface area of the frozen sample |
A S | m2 kg-1 | Specific surface area of the regolith available for adsorption |
α | Pa-1 | Langmuir adsorption constant (subscripts refer to the species) |
B | m3 molec-1 | Constant from Equation (1.b) |
C | kg m molec-1 s-1 | Constant from Equation (1.c) |
χ | dimensionless | Mass fraction (subscripts: Z = of dust; H2O = of water) |
D eff | m2s-1 | Diffusivity (subscripts: eff = Effective Diffusivity; 0 = time independent) When bolded represents a 2- element vector with [H2O HDO] |
e sys | dimensionless | Pumping efficiency (pressure ratio between chamber and QMS-inlet) |
G | dimensionless | Rate coefficient matrix |
γ Z | dimensionless | Volume fraction of dust in lag mantle |
k | dimensionless | Rate constant, Superscripts: ads = adsorption, des = desorption, X = cross-reaction substitution by vapor-phase species. When bolded represents a 2- element vector with [H2O HDO] |
k B | m2 kg s-2 K-1 | Boltzmann Constant (1.38 × 10-23) |
J | molec m-2 s-1 | Molecular flux at a point in the apparatus |
k | s-1 | Langmuir adsorption kinetic constant, Subscripts: H2O, HDO, X = substitution; Superscripts: ads = adsorption, des = desorption |
l | m | Thickness of an adsorbed monolayer of water (2.75 × 10-10) |
m H2O | kg molec-1 | Mass of a single water molecule (2.99 × 10-26) |
M H2O | kg mol-1 | Molar Mass (0.01802 for water) |
N A | molec mol-1 | Avogadro's Number (6.02 × 1023) |
n | molec m-3 | Number density of molecules |
p | Pa | Pressure (subscripts: sat = Saturated Vapor Pressure) |
R | m2K-1s-2 | Specific Gas Constant (462 for water) |
R u | J mol-1 K-1 | Universal Gas Constant (8.3145) |
ρ | kg m-3 | Density (subscripts: Z = of dust; reg = of regolith; H2O = of water) |
Ψ | J m-3 | Thermodynamic Adsorption Constant |
T | K | Temperature (subscripts: QMS = the tubing at the throat of the QMS) |
t | s | Time (subscripts: 0 = initial time) |
θ | dimensionless | Fraction of adsorption sites occupied by water molecules when bolded indicates a two-element vector with [H2O HDO] |
V | m3 s-1 | Pumping speed |
z | m | Thickness of dust lag (subscripts: 0 = initial time) |