Thermal Expansion

[@RANGAPIDATHALA]

very nice explanation about thermal expansion. got great intuition which make sense. Thankyou Prof

[@nishatripathi8720]

No words for this.. .....

[@rohitmadaan8885]

U made my day special 👌😊😊

[@jainandanmodi1124]

awesome!!!

[@siguerhakim4723]

Very nice explanation, Thanks for your fruitful course.

[@pinakinathbanerjee8095]

Nice graph, easy to understand

[@ashwinvenkat1239]

This lecture proposed for ionic crystal like NaCl what about covalent and metallic bonded crystals?

[@blzKrg]

Insightful.

[@jacobvandijk6525]

Nice explanation.

[@HarishSasikumar]

The potential curve that was drawn, looks like Lennard-Jones potential. In Wiki, it's variation is of the form (A/r)^12-(B/r)^6. But you have said it is of the for C-(D/r)+(E/r)^10. Which one is true?

[@HarishSasikumar]

thank you sir

[@robinswamidasan]

1/r^12 dominates 1/r^6 at small r, and vice-versa for larger r. While 1/r^10 dominates 1/r at small r, and vice-versa for larger r. So, naturally the curves look the same. Lennard-Jones is used largely for modelling inter-molecular forces, esp. covalent compounds. This lecture focusses on a simplistic model of an ionic crystal. That said, I would have liked to know how the 1/r^10 term is derived.

[@No-mind27]

Dear professor your lectures are inspiring. However, with due apologies, I would like to ask one question. Is it a right representation of repulsive energy curve in the first quadrant? If it is right, at equilibrium separation, resultant energy is minimum but the energy contribution from repulsive interaction seems zero which is not consistent with the theory that is explained. The repulsive curve could start at even higher R values if I am right. Please explain. Thanking you.

[@robinswamidasan]

Agree that the diagram is not accurate, but the concept is correct. At the point where resultant potential energy is a minimum, the rate of increase in the repulsive (electron cloud) interaction is equal to the rate of decrease in the Coulombic interaction. As R decreases further, the former exceeds the latter, giving an net increase in potential energy.

[@bhagyesh27]

IF we talk about the materials which actually shrinks while heating (Heat shrinks), then besides the polymerization mechanism to explain their respective tend, is it possible to explain that property with the energy position curve you explained? If Yes, How?

[@prasanthgupta5496]

Bhagyesh Purohit, I guess when polymerisation occurs the bonding changes which would in turn change the equations and constants describing the inter atomic attractions and repulsions. This would result in a smaller R0 value for heat shrinks.