Physical Chemistry

1. Chapter VI Interaction between Molecules Physical Chemistry Chemistry Department of Fudan University

2. §6−1 Intermolecular interaction Weak interactions between molecules 1873---van der Waals 1910 Noble Prize in Physics Chemistry Department of Fudan University

3. (1)Electrostatic interaction Keesom 1912 Dipole-dipole interactions between two polar molecules Chemistry Department of Fudan University

4. (2) Dipole-Induced-dipole interaction Debye 1920-1921 A molecule with permanent dipole can induce a dipole of a neighboring polarizability molecule (polarizability a). The interaction of the induced dipole with the permanent dipole can be written as: Chemistry Department of Fudan University

5. For similar molecules, if 1=2=, 1=2=, then Chemistry Department of Fudan University

6. (3) Dispersion interaction Transient dipole interactions 1930----London Chemistry Department of Fudan University

7. (4) Total Energy of intermolecular interactions Chemistry Department of Fudan University

8. Partition of van der Waals interaction Dipole moment Polarizability molecule Chemistry Department of Fudan University

9. The interaction energy of AB can be obtained using Variational Principle (Quantum mechanics) Chemistry Department of Fudan University

10. (5) Intermolecular potential energy (n=8-16) Chemistry Department of Fudan University

11. n=6, m=12 Lennard-Jones potential energy Chemistry Department of Fudan University

12. Lennard-Jones potential energy curve Chemistry Department of Fudan University

13. Chemistry Department of Fudan University

14. Van der Waals radius Primary alkane Chemistry Department of Fudan University

15. §6−2 Intermolecular interactions of gas For ideal gas : Chemistry Department of Fudan University

16. (1) Real gas and van der Waals equation For ideal gas, Z=1 Chemistry Department of Fudan University

17. Ideal gas Chemistry Department of Fudan University

18. Virial equation of state B, C, D: the second, third and fourth Virial coefficient Chemistry Department of Fudan University

19. Van der Waals equation: Vm= V / n Chemistry Department of Fudan University

20. (2) Critical and supercritical Critical point Critical pressure Critical volume Chemistry Department of Fudan University

21. (3) Corresponding state law Reduced variables: Chemistry Department of Fudan University

22. nitrogen methane propane ethylene Chemistry Department of Fudan University

23. At the critical point, pr, Tr and Vr all equal to 1 Chemistry Department of Fudan University

24. Chemistry Department of Fudan University

25. §6−3 Intermolecular interactions in liquid 1. The structure of liquid and radial distribution function J(R) The structure of liquid is the spatial distribution and arrangement of liquid molecules Long range---- disordered Short range--- ordered but components vary all the time Chemistry Department of Fudan University

26. The structure of liquid can usually be described by the radial distribution function, J(R) or the pair-correlation function g(R)： ---average particle density of liquid J(R)dR is the probability of finding another particle within a spherical shell with radius R and thickness dR defined by the center particle. Chemistry Department of Fudan University

27. Peak is close to the minimum of U2(R) wide-shell structure g2(R) ≈ 0 due to molecular repulsion Typical radial distribution curve of simple liquid Chemistry Department of Fudan University

28. The structure of liquid mainly depends on the density of liquid and is less perturbed by temperature Ar The J(R) curves of liquid Ar at different temperatures Chemistry Department of Fudan University

29. Ar The J(R) curves of liquid Ar at different densities As the increase of liquid density, the population of short-range ordered structures also increases Chemistry Department of Fudan University

30. if define the coordination number of liquid (Z) as the number of particles at the first coordination spherical shell, then Z is Chemistry Department of Fudan University

31. 2. Measurement and calculation of J(R) The radial distribution function can be determined experimentally by X-ray or neutron diffraction Diffraction intensity can be correlated with diffraction angle: where Chemistry Department of Fudan University

32. Theoretical calculation of J(R) VN—potential energy Molecular dynamics Monte Carlo simulation Chemistry Department of Fudan University

33. §6-4 Supermolecule chemistry and molecular assembly Supermolecule chemistry is concerned with molecular assemblies with special structure and function, consisting of two or more chemical species glued together through intermolecular interaction. 1. Supermolecule several components: donor and acceptors a vast number of components 2. Supermolecule assembly such as films, colloids Chemistry Department of Fudan University

34. Intermolecular interactions in supermolecule • Electrostatic • Hydrogen bonding • Metal-ligand interaction • -stacking • Induced dipole-induced dipole interaction • Hydrophobic effect Chemistry Department of Fudan University

35. Molecular recognition Supermolecular self-assembly Donor and acceptor selectivity Ordered structure Chemistry Department of Fudan University

36. Crown ether and cryptand Molecular recognition between crown ether and NH4+ Chemistry Department of Fudan University

37. Hydrogen bonding recognition and self-assembly Chemistry Department of Fudan University