.. _Definition of Symbols:


Definition of Symbols 
=====================

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Symbol                   Parameter                                          Unit
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:math:`I(\lambda, T)`    Spectral radiance		                            :math:`Wm^{-2} sr^{-1} \mu m^{-2}`
:math:`Q(T)`             Partition function                                 -- 
:math:`R`                Spectral resolution                                -- 
:math:`T`		         Temperature			                            :math:`K`
:math:`N`                Column integrated :math:`\text{H}_3^+` density	    :math:`m^{-2}`
:math:`b(\lambda)`		 Background level		                            :math:`Wm^{-2} sr^{-1} \mu m^{-2}`
:math:`\lambda`	         Wavelength			                                :math:`\mu m`
:math:`\sigma(\lambda)`  Wavelength dependent line width			        :math:`\mu m` 
:math:`s(\lambda)`	     Wavelength dependent line shift			        :math:`\mu m` 
:math:`g_{ns}`	         Spin weighting		                                --
:math:`J`	             Angular momentum quantum nbr	                    --
:math:`w_{if}`	         Emission frequency                                 :math:`cm^{-1}`
:math:`w_{upper}` 	     Upper energy level		                            :math:`cm^{-1}`
:math:`A_{if}`            Einstein A coefficient                            -- 
:math:`h`                Planck's constant		                            :math:`m^{-2} kg s^{-1}`
:math:`c`                Speed of light		                                :math:`m s^{-1}`
:math:`k`                Boltzmann's constant                               :math:`m^2 kg s^{-2} K^{-1}`
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