The document presents information on collision phenomena and excitation and ionization processes in plasmas. It discusses various types of collisions including elastic and inelastic collisions. It also describes different ionization processes such as excitation and ionization by electron collisions, thermal ionization, Penning ionization, and photoionization. Processes of ion-ion and ion-electron recombination like radiative and dielectronic recombination are also summarized. The presentation contains diagrams and equations to illustrate key concepts and is intended to provide an overview of these plasma phenomena.

1. Presentation on
Collision Phenomena
&
Excitation and Ionization
By Bijaya Basnet

2. Contents
1. Collision phenomena
- Collision phenomena
- Velocity distribution
- Elastic and Inelastic collision
- Reaction cross-section
2. Ionization and Excitation
- Excitation and ionization by electron collision
- Excitation and ionization by energetic particles or neutral particles
- Thermal ionization
- Penning ionization
- Photo ionization and Photo excitation
- Ion – Ion recombination
- Ion-electron recombination

3. Collision phenomena
From http://kayjayr-akshay.blogspot.com/2016/04/plasma-
fourth-state-of-matter.html

4. From
http://noyesharrigan.cmswiki.wikispaces.net/Maxwell-
Boltzmann+Distribution

5. temperature-of-electrons-and-heavy-
particles-in-the-plasma-as-a-function-of
pressure
From
https://www.researchgate.net/publication/257139583_Reducti
on_of_Oxide_Minerals_by_Hydrogen_Plasma_An_Overview

6. Comparison of Maxwellian and
Druyvesteyn Distributions
FromNicholasJamesBehlman
Thesisonplasma

7. Elastic and Inelastic collision
u1
u2
v1
v2
u1
u2
v1
v
v2

8. u1
u2
v1
u2
h𝑣

9. Mean free path and collision
frequency
+
+
+
+
+
+
+
+
+
+
+
+

10. Reaction cross-section
𝑑𝑛
𝑑𝑡
=−∝ 𝑛+ 𝑛− ∝ 6 × 3 ∝ 16 × 3

11. Excitation and Ionization
• Ionization and Excitation of atoms and
molecules by electron collision
Ionization Excitation

12. Ionization by electron impact
Cumulative (multistage)
ionization
Single (direct) ionization

13. • Ionization and Excitation of atoms and
molecules by energetic ions or neutral
particles
Ionization Excitation

14. Thermal ionization
From http://article.sapub.org/10.5923.j.instrument.20120105.02.html

15. Penning ionization
• 𝐴 + 𝐵∗
→ 𝐴+
+ 𝑒 + 𝐵
• Condition
Ionization potential of A is less than Excitation
potential of metastable particle𝐵∗

16. Photo-ionization
• 𝐴 + ℎ𝑣 = 𝐴+
+ 𝑒−
, ℎ𝑣 > 𝑉𝐼
Photo-excitation
• 𝐴 + ℎ𝑣 = 𝐴∗
, 𝑉𝐼> ℎ𝑣 > 𝑉𝐸

17. Ion-Ion recombination
• Radiative recombination
𝐴+
+ 𝐵−
→ 𝐴𝐵 + ℎ𝑣
• Mutual neutralization
𝐴+
+ 𝐵−
→ 𝐴∗
+ 𝐵∗
• Three body recombination
𝐴+
+ 𝐵−
+ 𝑀 → 𝐴𝐵 + 𝑀

18. Ion-electron recombination
• Radiative recombination
𝐴+ + 𝑒− → 𝐴∗ + ℎ𝑣
• Dielectronic recombination
𝐴+ + 𝑒− → 𝐴∗∗
𝐴∗∗ → 𝐴∗ + ℎ𝑣
𝐴∗∗ + 𝐵 → 𝐴∗ + 𝐵∗
• Dissociative recombination
𝐴𝐵+
+ 𝑒−
→ 𝐴∗
+ 𝐵∗
• Three body recombination
𝐴+
+ 𝑒−
+ 𝑒−
→ 𝐴 + 𝑒−
𝐴+ + 𝑒− + 𝐵 → 𝐴 + 𝐵

19. Any question?