# Chapter 14: Luminescence¶

## Example 14.1, page no-385¶

In :
# Penetration depth of electron

import math
#Variable Declaration
eb=10000.0              # Energy of incident beam in eV
k=1.2*10**-4            # Constant depending on marerial
b=0.151                 # Constant depending on marerial
e=1.6*10**-19           # charge of an electron

#Calculation
rc=k*(eb*e)**b

#Result
print('The penetration depth of the electron is %.4f µm'%(rc*10**6))

The penetration depth of the electron is 0.6998 µm


## Example 14.2, page no-386¶

In :
# Luminescent lifetime

import math
#Variable Declaration
ed=0.4                   # difference in energy level in eV
e=1.6*10**-19            # Charge of an electron
kT=0.025                 # temperature equivalent
q=10**8                  # constant

#Calculation
r=q*math.e**(-(ed/kT))

#Result
print('The escape rate per unit time = %.1f per sec\nTherefore, the luminescent lifetime is nearly %.0f sec'%(math.floor(r*10)/10,r))

The escape rate per unit time = 11.2 per sec
Therefore, the luminescent lifetime is nearly 11 sec