Creating an Ion

This example shows how to create a Ion object and access various pieces of metadata.

import astropy.units as u
import numpy as np

from fiasco import Ion

The CHIANTI database is organized around individual ions, with multiple types of datafiles attached to each ion. In keeping with the organization of the database, the primary unit of the fiasco library is the Ion object which can be created in the following way,

temperature = np.logspace(5, 7, 100) * u.K
ion = Ion('Fe 15', temperature)
print(ion)

CHIANTI Database Ion
---------------------
Name: Fe 15
Element: iron (26)
Charge: +14
Isoelectronic Sequence: Mg
Number of Levels: 0
Number of Transitions: 0

Temperature range: [0.100 MK, 10.000 MK]

HDF5 Database: /home/docs/.fiasco/chianti_dbase.h5
Using Datasets:
  ionization_fraction: chianti
  abundance: sun_coronal_1992_feldman_ext
  ip: chianti

This creates a Ion object for the Fe XV ion. Note also the same object can also be created in the following ways,

ion = Ion('iron 15', temperature)
ion = Ion('iron 14+', temperature)
ion = Ion('Fe XV', temperature)

The Ion object holds several basic pieces of metadata related to the particular ion,

print(ion.element_name)
print(ion.atomic_symbol)
print(ion.atomic_number)
print(ion.ion_name)
print(ion.charge_state)
print(ion.ionization_stage)
print(ion.abundance)

iron
Fe
26
Fe 15
14
15
0.0001258925411794166

The Ion object can also be indexed like an array in order to get information about the energy levels.

print(ion[0])

Level: 1
Configuration: 3s2
Spin: 0.0
Total Angular Momentum: 0.0
Orbital Angular Momentum: S
Energy: 0.0 eV

Each level also holds various bits of metadata

for i in range(5):
    lev = ion[i]
    print(f'Level {lev.level} {lev.configuration}, {lev.energy}')

Level 1 3s2, 0.0 eV
Level 2 3s 3p, 28.99271293001642 eV
Level 3 3s 3p, 29.71405299650078 eV
Level 4 3s 3p, 31.469669246314893 eV
Level 5 3s 3p, 43.63140325482594 eV