Chemical#

class optika.chemicals.Chemical(formula, is_amorphous=False, table=None)[source]#

Bases: AbstractChemical

An object that represents the optical properties of a chemical.

Uses the tabulated optical constants from Windt [1998].

Examples

Plot the indices of refractions of silicon and silicon dioxide.

import matplotlib.pyplot as plt
import astropy.units as u
import named_arrays as na
import optika

si = optika.chemicals.Chemical("Si")
sio2 = optika.chemicals.Chemical("SiO2")

wavelength = na.geomspace(10, 10000, axis="wavelength", num=1001) * u.AA

n_si = si.index_refraction(wavelength)
n_sio2 = sio2.index_refraction(wavelength)

fig, ax = plt.subplots(constrained_layout=True)
na.plt.plot(wavelength, n_si, label="silicon");
na.plt.plot(wavelength, n_sio2, label="silicon dioxide");
ax.set_xscale("log");
ax.set_xlabel(f"wavelength ({wavelength.unit:latex_inline})");
ax.set_ylabel("index of refraction");
ax.legend();

../_images/optika.chemicals.Chemical_0_0.png

Plot the wavenumbers of silicon and silicon dioxide

k_si = si.wavenumber(wavelength)
k_sio2 = sio2.wavenumber(wavelength)

fig, ax = plt.subplots(constrained_layout=True)
na.plt.plot(wavelength, k_si, label="silicon");
na.plt.plot(wavelength, k_sio2, label="silicon dioxide");
ax.set_xscale("log");
ax.set_xlabel(f"wavelength ({wavelength.unit:latex_inline})");
ax.set_ylabel("wavenumber");
ax.legend();

../_images/optika.chemicals.Chemical_1_0.png

Attributes

`file_nk`	The path to the Windt [1998] file containing the index of refaction, \(n\), and the wavenumber, \(k\).
`formula`	the empirical formula of the chemical compound.
`formula_latex`	LaTeX representation of the chemical formula, with appropriate subscripts.
`is_amorphous`	Boolean flag controlling whether the chemical is amorphous or crystalline.
`shape`	The array shape of this object.
`table`	Name of the table of chemical constants.

Methods

`__init__`(formula[, is_amorphous, table])
`absorption`(wavelength)	The absorption coefficient of this chemical for the given wavelength.
`index_refraction`(wavelength)	The index of refraction of this chemical for the given wavelength.
`n`(wavelength)	The complex index of refaction of this chemical for a given wavelength
`to_string`([prefix])	Public-facing version of the `__repr__` method that allows for defining a prefix string, which can be used to calculate how much whitespace to add to the beginning of each line of the result.
`wavenumber`(wavelength)	The wavenumber of this chemical for the given wavelength.

Inheritance Diagram

Parameters:

formula (str | AbstractScalar)
is_amorphous (bool)
table (None | str)

absorption(wavelength)#

The absorption coefficient of this chemical for the given wavelength.

Parameters:: wavelength (Quantity | AbstractScalar) – The wavelength of light in vacuum for which to compute the absorption coefficient.

index_refraction(wavelength)#

The index of refraction of this chemical for the given wavelength.

Parameters:: wavelength (Quantity | AbstractScalar)
Return type:: AbstractScalar

n(wavelength)#

The complex index of refaction of this chemical for a given wavelength

Parameters:: wavelength (Quantity | AbstractScalar)
Return type:: AbstractScalar

to_string(prefix=None)#

Public-facing version of the __repr__ method that allows for defining a prefix string, which can be used to calculate how much whitespace to add to the beginning of each line of the result.

Parameters:: prefix (None | str) – an optional string, the length of which is used to calculate how much whitespace to add to the result.
Return type:: str

wavenumber(wavelength)#

The wavenumber of this chemical for the given wavelength.

Parameters:: wavelength (Quantity | AbstractScalar)
Return type:: AbstractScalar

property file_nk: ScalarArray#: The path to the Windt [1998] file containing the index of refaction, \(n\), and the wavenumber, \(k\).

formula: str | AbstractScalar = <dataclasses._MISSING_TYPE object>#

the empirical formula of the chemical compound.

For example, water would be expressed as "H2O" and hydrogen peroxide would be expressed as "H2O2".

property formula_latex: str#: LaTeX representation of the chemical formula, with appropriate subscripts.

is_amorphous: bool = False#: Boolean flag controlling whether the chemical is amorphous or crystalline.

property shape: dict[str, int]#: The array shape of this object.

table: None | str = None#

Name of the table of chemical constants.

Common options are "palik", "llnl", and "windt". The database is the same as the IMD code [Windt, 1998]. The default value, None, usually means concatenating the tables in Palik [1997] and Henke et al. [1993].