Excited-State-Quantifier

A python repository for quantitative analysis of excited state populations and more relevant to laser spectroscopy.

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What it does ?

Using known experimental parameters compute the molecular concentration of the excited state molecules and more. See example notebooks for detail.

Example :

results = core.excitation_analysis(
    P_avg=0.75 * 1e-3,          # W
    delta_P_avg=0.03 * 1e-3 ,    # error in  W
    rep_rate=1000,          # Hz, repition rate of laser 
    lambda_nm=316,         # wavelength / nm
    absorbance=0.99537 ,    # absorbance (effect of dilution included)
    delta_absorbance=0.085, # error in absorbance
    epsilon=16840,       # mol L-1
    path_length_mm=2,    # mm
    beam_diameter_um=244,  # beam spot diamater (um)
    delta_beam_diameter_um=7 # error in beam spot
)
core.print_full_results(results)

# output
===== RESULTS =====
Photons per pulse: 1.193086e+12 ± 4.772343e+10  (4.000%)
Fraction absorbed: 8.989282e-01 ± 1.978175e-02  (2.201%)
Concentration: 2.955374e-04 ± 2.523753e-05 M (8.540%)
Concentration: 2.955374e-01 ± 2.523753e-02 mM (8.540%)
Probe volume: 9.351893e-08 ± 5.365840e-09 L (5.738%)
Number of molecules: 1.664420e+13 ± 1.712372e+12  (10.288%)
Excitation fraction: 6.443676e-02 ± 7.252717e-03  (11.256%)
Excitation fraction (in %): 6.44368 ± 0.72527  (11.256%)
Absorbed photons: 1.072498e+12 ± 4.896352e+10  (4.565%)
-------------------
 << Under linear regime >>
Num molecules in the excited state (t=0): 1.072498e+12 ± 4.896352e+10  (4.565%)
===================

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Requires

Python3, numpy and optionally matplotlib for plotting

Following parameters can be computed.

relevant to pump-probe spectroscopy such as transient absorption

• Photons per pump pulse

• Fraction of pump photons absorbed

• Sample concentration, S0 (given epsilon and absorbance)

• Probe volume in cm3 and L

• Number of molecules in probe volume

• Excitation fraction

  • in absolue number
  • in percent

• If linear absoprtion is assumed then number of excited state molecules

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Excited state properties

• Epsilon from known parameters
• Effect of absorption of excited state to probe (i.e. probe attenuation)

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Variation of ground and excited state absorption across path-length

• Depth dependent profile of
  • Excited state concentration
  • Probe intensity