1. Neeraj Sharma, Carine Gilliéron, B. Klaas Nauta & Timothy W. Schmidt
STRUCTURE OF NAPHTHALENE DIMER INFERRED FROM SPECTRA OF NAPHTHALENE DIMER - ARGON VAN DER WAALS COMPLEXES
Neeraj Sharma, Carine Gilliéron,
B. Klaas Nauta & Timothy W. Schmidt

3. Structures of aromatic dimers
Prototypical intermolecular forces
Competition between electrostatics and p-stacking
Important in biological systems (protein folding, DNA stability) and other self-assembly paradigms

4. Structures of aromatic dimers: Benzene
August 15, 1975: Klemperer and co-workers, “Benzene Dimer: A polar molecule”.
March 29, 2006: Young Choon Park and Jae Shin Lee, The difference between the estimated CCSD(T) basis set limit electronic binding energies for the T and PD shapes appears to amount to more than 0.3 kcal/mol, indicating the PD shape is a more stable configuration than the T shape for this dimer in the gas phase. ? or

5. Structures of aromatic dimers: Anthracene
April 5, 2000: Gonzalez and Lim, “crossed (D2d) and parallel-displaced (C2h) structures”.

6. Structures of aromatic dimers: Naphthalene
Sept. 2002, Walsh, MP2 &c,
March 24, 2003, Fujiwara and Lim, R2PI
April 29, 2004: Grimme, DFT

7. Structures of aromatic dimers: Naphthalene
Np, 80°C in He
7bar
Np+ clusters
Np+ clusters

8. Structures of aromatic dimers: Naphthalene

10. Structures of aromatic dimers: NaphthaleneNp
Naph10
Mass = 1280
Np2

11. Spectra Wavenumber (cm-1 ) n (cm-1) 31600 31800 32000 32200 32400
Decamer
Nonomer
Octamer
31600
31800
32000
32200
32400
32600
32800
33000
Wavenumber (cm-1 -1 )
Heptamer
Hexamer
Pentamer
Tetramer
Trimer
Dimer
Origin
Monomer
n (cm-1)

12. World Records?
The “Klaaswagen”

13. Mothballs in space: The struggle against nanomoths...

14. Structures of aromatic dimers: NaphthaleneNp
Naph10
Mass = 1280
Np2Arn
Np2

15. Structures of aromatic dimers: Naphthalene

16. Structures of aromatic dimers: Naphthalene
Np2Ar mass peak yields much sharper spectrum than the Np2 mass peak.
This spectrum cannot derive from higher Np clusters!

17. Structures of aromatic dimers: Naphthalene

18. Structures of aromatic dimers: Naphthalene
Differences in NpArn spectra… does one monomer shake off the argons more easily?
Selection in the NpAr spectrum… is it only the T-shaped structure that can retain argons?