Source code for skultrafast.unit_conversions

"""
This module contains functions to covert between units of energy.
"""
import numpy as np
from scipy.constants import physical_constants, c


[docs]
c_cm = c * 100


[docs]
names = dict(
    cm="wavenumbers in 1/cm",
    fs="period in femotoseconds",
    ps="period in picoseconds",
    nm="wavelength in nanometers",
    eV="energy in electron Volt",
    THz="frequency in THz",
    dichro="Dichroic ratio (para/perp)",
    angle="relative angle between transition dipole moments in degrees",
    aniso="Anisotropy (para-perp)/(para+2*perp)",
    kcal="energy in kcal/mol",
    invps="energy in inverse picoseconds",
)




[docs]
def make_doc(func):
    a, b = str.split(func.__name__, '2')
    func.__doc__ = ('%s to %s' % (names[a], names[b])).capitalize()
    return func



@make_doc

[docs]
def fs2cm(t):
    return 1 / (t*1e-15*c_cm)



@make_doc

[docs]
def cm2fs(cm):
    return 1e15 / (cm*c_cm)



@make_doc

[docs]
def ps2cm(t):
    return 1 / (t*1e-12*c_cm)



@make_doc

[docs]
def cm2ps(cm):
    return 1e12 / (cm*c_cm)



@make_doc

[docs]
def nm2cm(nm):
    return 1e7 / nm



@make_doc

[docs]
def nm2eV(nm):
    return cm2eV(nm2cm(nm))



@make_doc

[docs]
def cm2nm(cm):
    return 1e7 / cm



@make_doc

[docs]
def cm2eV(cm):
    eV_m = physical_constants['electron volt-inverse meter relationship'][0]
    eV_cm = eV_m / 100
    return cm / eV_cm



@make_doc

[docs]
def eV2cm(eV):
    eV_m = physical_constants['electron volt-inverse meter relationship'][0]
    eV_cm = eV_m / 100
    return eV * eV_cm



@make_doc

[docs]
def THz2eV(THz):
    hertz_eV = physical_constants['hertz-electron volt relationship'][0]
    return THz * 1e12 * hertz_eV



@make_doc

[docs]
def eV2THz(eV):
    eV_Hertz = physical_constants['electron volt-hertz relationship'][0]
    return eV * eV_Hertz * 1e-12



@make_doc

[docs]
def eV2nm(eV):
    return cm2nm(eV2cm(eV))



@make_doc

[docs]
def cm2THz(cm):
    return 1 / fs2cm(cm) / 1e-3



@make_doc

[docs]
def THz2cm(THz):
    return cm2fs(1e3 / THz)



@make_doc

[docs]
def dichro2angle(d):
    return np.arccos(np.sqrt((2*d - 1) / (d+2))) / np.pi * 180



@make_doc

[docs]
def angle2dichro(deg):
    rad = np.deg2rad(deg)
    return (1 + 2 * np.cos(rad)**2) / (2 - np.cos(rad)**2)



@make_doc

[docs]
def angle2aniso(deg):
    ang = np.deg2rad(deg)
    return 2 / 5 * (3 * np.cos(ang)**2 - 1) / 2



@make_doc

[docs]
def aniso2angle(r):
    return np.arccos(np.sqrt((r*10/2 + 1) / 3)) / np.pi * 180



@make_doc

[docs]
def cm2kcal(cm):
    return cm * 2.859e-3



@make_doc

[docs]
def kcal2cm(kcal):
    return kcal / 2.859e-3



@make_doc

[docs]
def invps2cm(invps):
    return 1 / (invps*1e-12*c)



@make_doc

[docs]
def cm2invps(cm):
    return 1 / (cm*1e-12*c)