Chapter 5, Problem 5.132CP

Interpretation Introduction

Interpretation:

‘Ionisation energy’ should be identified.

Concept introduction:

According to the Einstein equation the energy required to remove an electron is the summation binding energy or ionisation energy of an electron ( $E_i$ ) and its kinetic energy ( $E_k$ ). Thus $E=E_k+E_i$. The binding energy is the ionisation energy of an atom which is required to remove the outermost electron of the atom. Thus in photoelectron spectroscopy (PES) the binding energy of the atom has to be determined.

Now the kinetic energy of the electron can be determined by the equation $E_k=\frac{1}{2}m{v}^2$ , where m = mass of the electron and v = velocity of the electron.

The energy of the incident light can be determined by Planck’s equation $E=h\upsilon$ , where h = Planck’s constant and $\upsilon$ = frequency of light which is related to the wave length ( $\lambda$ ) by the equation $\upsilon =\frac{c}{\lambda }$ , where c = velocity of light.

Given:

The wave length of the incident light is 48.2nm. The mass and velocity of electron is $9.109\times {10}^{-31}$ and $2.371\times {10}^{6}m/s$ respectively.

The Planck’s constant, h = $6.626\times {10}^{-34}Joule.\sec$.

The light of velocity c = $3\times {10}^{8}m/s$

To determine:

The iIonisation energy of selenium atom.