![Page 1: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/1.jpg)
e-
Inner region
Outer region
Jonathan Tennyson
Quantemol
University College London
UCL
April 2014
Electron collisions for
technological plasma models
![Page 2: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/2.jpg)
Founded in 2004 as a University College London spin-off providing user friendly interfaces for sophisticated academic codes
Distribute 3 software packages:
UK R-matrix Code
GlobalKin Code Feedstock gases
Power Heat
Waste products
HPEM Code
![Page 3: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/3.jpg)
User friendly interface on top of Kushner’s HPEM
VS
![Page 4: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/4.jpg)
2D results
1D graphs and EEDF
Data export for comparison
![Page 5: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/5.jpg)
Power coupling: CCP
Ar/Cl2: 0.8/0.2
2Freq: 10 MHZ 500 W 100 MHZ 750 W
Flow: 300 sccm
Electron kinetics: Monte-Carlo Solver
Wafer Size: 300 mm Chemistry: 10 species, 37 reactions
Running time: approx. 1 to 1.5 days
Electron Density Distribution
![Page 6: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/6.jpg)
Extensively validated
and widely used in
industry
Uniquely designed for
simulation of low
pressure plasma
Has large variety of
physical model options
![Page 7: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/7.jpg)
Released: March 2014
Intuitive interface
Multiple visualisation
capability
Easy-to-use reactor “painter”
Example library
Job runner with single and
simultaneous queuing
Parameter optimization
capability
![Page 8: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/8.jpg)
An Introduction to the
programme
![Page 9: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/9.jpg)
Processes: at low impact energies
Elastic scattering
AB + e AB + e
Electronic excitation
AB + e AB* + e
Dissociative attachment / Dissociative recombination
AB + e A + B
A + B
Vibrational excitation
AB(v”=0) + e AB(v’) + e
Rotational excitation
AB(N”) + e AB(N’) + e
Impact dissociation
AB + e A + B + e
Impact ionization (e,2e)
AB + e AB + e + e
![Page 10: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/10.jpg)
Processes: at low impact energies
Photoionisation
AB + hn AB+ + e
All go via (AB)** . Can also look for bound states
Also consider:
New feature in
![Page 11: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/11.jpg)
H H
Inner region
Outer region R-matrix
boundary
The R-matrix method J. Tennyson, Electron - molecule
collision calculations using the R-matrix
method, Phys. Rep., 491, 29 (2010).
e-
![Page 12: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/12.jpg)
Electron – water rotationally resolved cross sections:
Differential cross sections (DCS) at 6 eV
DJ=1
DJ=0
DJ=all
*
Cho et al (2004)
Jung et al (1982)
R-matrix (2004)
![Page 13: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/13.jpg)
A. The UK Molecular R-Matrix Codes
• Freely available online
• People can join as users on CCPForge
• Comprehensive but hard to use
(Can take a whole PhD (3 years) to correctly run one molecule!)
B. Quantemol-N
• Easy to use graphical interface
• Very simple input, requires little scientific knowledge or training
• Extra features (ionisation, dissociative attachment estimator,
high energy electronic excitation, etc)
Two methods of doing R-matrix calculations:
CCPQ Collaborative Computational Project Q - Quantum Dynamics
![Page 14: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/14.jpg)
Main advantages of using Quantemol-N:
User friendly interface, which vastly
simplifies setting up an R-matrix simulation.
Full tutorial system to reduce learning curve.
Library containing 40+ examples.
Easy to use results format.
24/7 service support from Quantemol team.
![Page 15: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/15.jpg)
Quantemol-N 4.1 can calculate:
Elastic cross-sections
Electronic excitation cross-sections (extended to high energies with BEf)
Super-elastic cross-sections between excited states
Electron impact dissociation
Scattering reaction rates
Resonance parameters
Dissociative electron attachment cross-sections estimator
Differential cross-sections
Momentum transfer cross-sections
Rotational excitation cross-sections
Atomic cross-sections
Electron impact ionisation at all energies
Red: features not in standard code
![Page 16: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/16.jpg)
Examples obtained using
Quantemol-N
![Page 17: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/17.jpg)
Chlorine – Dissociative Attachment
DZP basis for the target and frozen bond-length of 1.988Angstrom.
CAS-CI representation: 20 core electrons are frozen (Cl 1s, 2s and 2p orbitals).
14 active electrons are distributed as: (4 - 6σg, 4 - 5σu, 2πu, 2πg)14.
Lowest virtual orbitals of σg, σu and πu retained in the scattering calculation
48 target states in the close-coupling expansion.
Dissociative electron attachment cross sections for Cl2
Calculations used the DEA cross section estimator in Quantemol-N
![Page 18: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/18.jpg)
Oxygen – Dissociative Attachment
Calculations: 6-311G* target basis at frozen bond length of 1.2144 A.
Target CAS: 4 core electrons frozen,and10 electrons in 12 valence orbitals:
(1σg, 1σ
u)4 (2σ
g, 3σ
g, 2σ
u, 3σ
u, 1π
u, 2π
u, 1π
g)12.
Scattering calculation augmented with the 4σg, 4σ
u and 2π
g orbitals.
48 states retained in close-coupling expansion.
![Page 19: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/19.jpg)
Silane Ramsauer–Townsend minimum and
other features in good agreement
with experiment and theory
![Page 20: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/20.jpg)
CF2 radical
-Highly reactive and therefore difficult species to
work with in the laboratory
R-matrix calculation
- Equilibrium geometry (C2v point group)
- Target Gaussian basis set: cc-pVTZ
- Included 8 target states
- Level: Full valence CI (MCSCF orbitals)
- R-matrix radius: 10 a0
![Page 21: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/21.jpg)
CF2 radical
![Page 22: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/22.jpg)
CF2 radical
![Page 23: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/23.jpg)
Thanks for listening
UK R-matrix Code
GlobalKin Code Feedstock gases
Power Heat
Waste products
HPEM Code
![Page 24: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/24.jpg)
Thank you for listening!
Some useful websites:
http://cccbdb.nist.gov/ - Good for
geometries, data comparisons
https://bse.pnl.gov/bse/portal - Basis set
database
Contact: Anna Dzarasova, +44 (0) 207 679 34 76, [email protected]
![Page 25: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/25.jpg)
Methane
![Page 26: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/26.jpg)
Electron – water (rotationally averaged)
elastic cross sections
Integral cross section
A Faure, JD Gorfinkel & J Tennyson, J Phys B, 37, 801 (2004)
![Page 27: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/27.jpg)
Neopentane -17 atoms - no previous theory - Ramsauer-Townsend (RT) minimum at ~0.2eV in good agreement with experiment. - Bigger molecules are possible.
![Page 28: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/28.jpg)
Electron – water Momentum transfer cross section
Cho et al (2004)
Johnstone & Newell
![Page 29: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/29.jpg)
CF2 C6H6 C5H12 SiH4
Cl2 C3H4 NO2 C2H6
O2 C2 NO C3H8
H2O C3H6 O3 HCN
H3+ CaF+ PH3 HNC
CH4 CaF BF3 SiO
C3N CF N2 CS
Cl2O CO2 CO F2
CONH3 BF3 H2 HBr
Progress...
... plus a whole host of work done elsewhere.
![Page 30: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/30.jpg)
Dominant interactions Inner region: can write exact H
Exchange
Correlation Adapt quantum chemistry codes
Outer region Long-range multipole polarization potential
Adapt electron-atom codes
High l functions required
Integrals over finite volume
Include continuum functions
Special measures for orthogonality
CSF generation must be appropriate
Many degenerate channels
Long-range (dipole) coupling
Boundary Target wavefunction has zero amplitude
![Page 31: Electron collisions for technological plasma models...Quantemol-N 4.1 can calculate: Elastic cross-sections Electronic excitation cross-sections (extended to high energies with BEf)](https://reader030.vdocument.in/reader030/viewer/2022040323/5e640f3c56b83c4cb6304a8c/html5/thumbnails/31.jpg)
R-matrix method for electrons: inner region wavefunction
Yk = A Si,j ai,j,k fiN hi,j + Si bj,k fj
N+1
fiN= target states = CI target built from nuclear centred GTOs
fjN+1= L2 functions
H H
e inner region
hi,j = continuum orbitals = GTOs centred on centre of mass
(within the Fixed-Nuclei approximation)
a
A = Anti-symmetriser
ai,j,k and bj,k variationally determined coefficients