latex-ism-emission-lines

This code implements a conversion of emission lines formatted according to the convention of the Meudon PDR code (http://ism.obspm.fr/pdr.html).

Getting started

This code is designed in a very simple way, in a single Python file ism_lines_helpers.py, so it can be easily copied into your project. Only built-in libraries are used so the only dependency is Python >= 3.0.

Lines formatted according to the Meudon PDR standard

The emission line are supposed to be formatted according to the Meudon PDR standard species_highlevels__lowlevels.

For instance, h2_v0_j3__v0_j1 represents the transition $J=3-2$ of $H_2$ at $\nu=0$.

Usage

The main function is line_to_latex which returns a LaTeX printable version of a formatted emission line.

Other available functions are the following

• molecule_and_transition: segment the formatted emission line in order to return the formatted chemical species and energy transition,
• molecule: returns only the formatted chemical species,
• transition: returns only the formatted energy transition,
• is_line_of: returns whether the line belongs to a given molecule,
• filter_molecules: returns the sublist of a formatted emission lines list containing only lines of species contained in a given list of chemical species,
• molecules_among_lines: returns a list of chemical species present in a list of formatted emission lines (without duplicates),
• molecule_to_latex: returns a LaTeX printable version of a formatted chemical species,
• transition_to_latex: returns a LaTeX printable version of a formatted energy transition.
• remove_hyperfine: return a shorter version of the formatter line without hyperfine levels.
• is_hyperfine: returns whether a line corresponds to a degenerate energy level or whether two lines belong to the same hyperfine structure.

After moving the file ism_lines_helpers.py in a directory that is in your Python path (if it is not the case, consider using the command sys.path.append(path_of_containing_folder)), you can import any of the above functions. For instance

from ism_lines_helpers import line_to_latex

Examples

line_to_latex("h2_v0_j3__v0_j1")
>>> '$H_2$ ($\\nu=0$, $J=2$ $\\to$ $\\nu=0$, $J=0$)'

$H_2$ ($\nu=0$, $J=2$ $\to$ $\nu=0$, $J=0$)

line_to_latex("h2o_j1_ka1_kc1__j0_ka0_kc0")
>>> '$H_2O$ ($J=1$, $k_a=1$, $k_c=1$ $\\to$ $J=0$, $k_a=0$, $k_c=0$)'

$H_2O$ ($J=1$, $k_a=1$, $k_c=1$ $\to$ $J=0$, $k_a=0$, $k_c=0$)

line_to_latex("h_el3d_j5_2__el1s_j1_2")
>>> '$H$ ($3d$, $J=\\frac{5}{2}$ $\\to$ $1s$, $J=\\frac{1}{2}$)'

$H$ ($3d$, $J=\frac{5}{2}$ $\to$ $1s$, $J=\frac{1}{2}$)

More examples are available in examples.ipynb, especially for the other functions. An HTML version of this notebook is also available as documentation.

Customization

This code is designed so that it can be enriched with new features. You can add or modify

• the LaTeX writing of chemical species,
• the different eligible aliases of some chemical species,
• the LaTeX writing of energies.

To modify these variables, simply edit the Python file and modify the following dictionaries.

# Molecular names to LaTeX
_molecules_to_latex = {
    "h": "H",
    "h2": "H_2",
    # ...
}

# Molecular names aliases
_molecules_aliases = {
    "13co": "13c_o",
    "c18o": "c_18o",
    # ...
}

# Energy to LaTeX
_energy_to_latex = {
    "j": "J={}",
    "v": "\\nu={}",
    # ...
}

# Electronic state to LaTeX
_elstate_to_latex = {
    "s": "{}s",
    "p": "{}p",
    # ...
}

# Literal to LaTeX
_literal_to_latex = {
    "pp": "p=+",
    "pm": "p=-"
}