{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

18_562ln08 - MIT OpenCourseWare http/ocw.mit.edu 5.62...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
MIT OpenCourseWare http://ocw.mit.edu 5.62 Physical Chemistry II Spring 2008 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms .
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
5.62 Lecture #18: Model Intermolecular Potentials Readings: Hill, pp. 261-274 Intermolecular potentials are interactions between molecules — up to this point, particles are treated as independent, ideal particles that do not interact. Approximation okay for gas molecules at low pressure All atoms and molecules interact with one another, even inert gas atoms. Interaction potential between non-polar atoms Attractive forces: London dispersion or van der Waals force. Induced dipole interaction due to fluctuations in electron distribution: Charge 1 distribution on one atom is “off center” due to fluctuation. The U ( r ) r 6 resulting electric dipole induces a temporary dipole on the other can be derived by QM atom. Dipole-dipole attraction. perturbation theory Repulsive forces: Due to electron orbital overlap (“overlap” or “Pauli” repulsion) Difficult to derive explicit distance dependence : usually treated as strongly repulsive, e.g.
Image of page 2
5.62 Spring 2008 Lecture #18, Page 2 U(r) 1 OR U(r) exp[–a(r – R min ) d ] (d is odd integer) r 12 Add attractive and repulsive portions of potential — resulting interaction potential looks like that for a diatomic molecule!! Two Ar atoms form a non-covalent "bond", but the binding
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern