1. Molecular Nanotechnology
Presented By,
Gopal Bharathwaj
9/16/2018
Molecular Nanotechnology

2. Molecular Nanotechnology
Agenda
What is molecular manufacturing ?
Comparison between various design and modeling techniques.
Introduction to molecular machines.
Sufficiency of current modeling methods.
A family of six degree of freedom positional devices.
Conclusion
9/16/2018
Molecular Nanotechnology

3. Molecular manufacturing
Manufactured products are made from atoms.
Rearranging the atoms in an already existing product helps us to develop new products.
Today’s manufacturing methods are very crude at the molecular level.
We will be able to snap together the fundamental building block of nature easily, inexpensively and in almost all the arrangements that we desire.
9/16/2018
Molecular Nanotechnology

4. Various design and modeling techniques
Chemical Vapor Deposition (CVD)
Molecular Mechanics
Ab initio quantum analysis
9/16/2018
Molecular Nanotechnology

5. Carbon Vapor Deposition (CVD)
Hydrogen abstraction during CVD involves a radical reaction between atomic hydrogen and the gas with H bonded to carbon on the surface producing H2.
9/16/2018
Molecular Nanotechnology

6. Molecular Nanotechnology
Molecular Mechanics
Modeling of the positions of the nuclei of individual atoms.
The individual nuclei are usually treated as point masses.
And the potential energy E, is a function of distance between the nuclei (r).
9/16/2018
Molecular Nanotechnology

7. Example of Molecular Mechanics
Consider the hydrogen atom.
It consists of two nuclei.
The function E(r) depends on two major factors:
Inter nuclei repulsion.
Interaction between the nuclei and the electrons.
Hence the two hydrogen nuclei will adopt a position so as to minimize E(r).
9/16/2018
Molecular Nanotechnology

8. Molecular Nanotechnology
Example (contd…)
As the inter nuclei distance (r) increases.
The potential energy of the system increases.
Nuclei experience a restoring force that returns them to their original distance.
On the other hand, as r decreases
The two nuclei are pushed closer together and
The restoring force pushes them farther apart.
9/16/2018
Molecular Nanotechnology

9. Molecular Nanotechnology
Example (contd…)
Knowing the positions r1,r2,…rn of N nuclei E(r1,r2,…rn ) gives the potential energy of the system.
If we know the potential energy as a function of the nuclear positions
Determine the forces acting on the individual nuclei.
Compute the evolution of their positions over time.
The particular values of E at particular points are determined by Schrodinger’s equation.
9/16/2018
Molecular Nanotechnology

10. Ab initio quantum analysis
Process that uses the mechanical positioning of reactive species to control chemical reactions, by either providing activation energy or selecting between alternative reaction pathways allowing us to construct a wide range of complex molecular structures.
9/16/2018
Molecular Nanotechnology

11. Ab initio quantum analysis (contd…)
Applying position control to reactions will require the tools to have certain properties
Have proper chemical properties.
Be relatively small to reduce steric interactions with the work piece.
Capable of being chemically and mechanically stable under thermal motions and strains induced during positioning.
Be bound to a system that can transfer forces and torques to reactive portions of the tool.
Be selective between alternative reactions.
Be easily made.
9/16/2018
Molecular Nanotechnology

12. Ab initio quantum analysis (contd…)
Method of creating the radical.
The obvious approaches are…
The C-H bond problem.
9/16/2018
Molecular Nanotechnology

13. Ab initio quantum analysis (contd…)
How to solve the C-H bond problem?
Attack by two weak radical strategy.
Photo exhibiting technique
9/16/2018
Molecular Nanotechnology

14. Ab initio quantum analysis (contd…)
R1-H-R2 HF
GVBCI-SCF
CCCI
DCCI
HF*SD CI
GVB*SD CI
H-H-Ha
24.3
9.9
10.3
10.5(9.6)c
10.3(10.3)
CH3-H-CH3
34.9
27.8
29.8
17.5
22.5(19.5)
20.4(18.8)
H-H-CCH
11.6
8.0
5.4
0.8
4.5(3.2)
3.3(2.7)
CH3-H-CCH
14.6
8.6
10.2
-2.9bb
4.2(2.0)
2.2(1.3)
(CH3)3C-H-CCH
11.0
5.9
-7.0
0.45(-2.78)
C6H6-H-CCH
18.3
12.0
14.3
-0.7
7.7(4.1)
HCC-H-CCH
30.0
22.9
24.1
17.0(13.7)
14.6(12.9)
9/16/2018
Molecular Nanotechnology

15. Sufficiency of current modeling methods
It is quite possible to adequately model the behavior of molecular machines that satisfy two constraints
They are built from sufficiently stable parts.
The synthesis of the parts is done by using positionally controlled reactions.
9/16/2018
Molecular Nanotechnology

16. A new family of six degree of freedom positional devices
Stewart Platform
The double tripod
The crank
Five strut crank
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Molecular Nanotechnology

17. Molecular Nanotechnology
Stewart Platform
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Molecular Nanotechnology

18. Molecular Nanotechnology
The double Tripod
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Molecular Nanotechnology

19. Molecular Nanotechnology
The Crank
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Molecular Nanotechnology

20. Molecular Nanotechnology
Five Strut Crank
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Molecular Nanotechnology

21. Molecular Nanotechnology
Conclusion
Derive detailed description of the behavior of the proposed systems.
Substantially reduce the development time for the complex molecular machines.
It is possible to debate how long it will be before we achieve robust molecular manufacturing capability.
We will get there sooner if we develop and make intelligent use of molecular design tools and computational models.
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Molecular Nanotechnology

22. Molecular Nanotechnology
References
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Molecular Nanotechnology

23. Molecular Nanotechnology
Questions???
9/16/2018
Molecular Nanotechnology