Gas mixtures
This page presents a list of all available molecular mixtures.
This list is presented as a table that contains the following columns (Fig. 1):
Id - internal mixture identifier in system database;
Title - verbal description of the mixture;
Mixing ratio, % - mixing ratio as a list of pairs: "molecular species" : "percentage in mixture";
Airy - if this column contains “Yes” the air-broadening halfwidth for Lorentz profile and the shift of the line position by air pressure are taken into account on spectra simulation.
The first ten mixtures are the mixtures of atmospheric air at the H=0 altitude for different latitudes (high, mean, tropics) and different seasons (summer and winter). The first five mixtures correspond to the US Standard Atmosphere 1976 model (http://www.pdas.com/atmos.html), the next five corresponds to models of the Institute of Atmospheric Optics (Russia, Tomsk) (V.E. Zuev, V.S. Komarov. Modern problems of atmospheric optics, Vol 1. Statistical models of temperature and gaseous components of the atmosphere, 1986, in Russian). All other mixtures are pure molecular gases of the molecules in HITRAN.
Registered users have a possibility to create their own mixtures. For this purpose, the user must select the User-defined as Origin of the mixture via the switch above the list of mixtures. To define a new mixture press the button Create mixture. After you have pressed this button the form Create mixture appears. The rightmost column of the table of User-defined mixtures allows to update (by the button
) or delete (by the button 
) previously created mixtue. For create and update mixture the same form is used (Fig. 2).The create/update mixture form the follownng fields:
- The Title text field.
- The table of mixing ratios. To manage this table use small button in the bottom-left corner of the table, from the left to the right: Add row, Edit selected row, Save selected row and Cancel editing selected row. To select a row click on it. To delete selected row click on the Trash button on the right column of the table.
- The Consider Lenv and Pshift checkbox. If it is checked the Lorentz half-width of jth spectral line L is calculated by the formula Lj = Cj·Ljself + (1-Cj)·Ljenv, where Cj is the isotopologue concentration of jth spectral line, Ljself is the self-broadened half-width of the line, and Ljenv s the environment-broadened half-width of the line. The shift of the line position by air pressure is also taken into account. If the checkbox is unchecked Ljself is selected as the Lorentz half-widthand the shift of the line position by air pressure is not taken into account.
- The Normalization of volume share values drop-down list that allows to select whether the normalization of volume share values is neccessary.
- The Save and Cancel buttons to finish creation or editing process.
Fig.2. The create/update mixture form