ENG045_HW.3.SOLNS

ENG045_HW.3.SOLNS - DATE: DUE: ENG45, Solution to homework...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
DATE: October 16, 2011 DUE: October 21, 2011 ENG45, Solution to homework set #3. 1. Weak interactions. We can write the van der Waals’ interaction energy between two atoms separated by the distance r , in the following three ways V ( r ) = 4 E 1 p P σ 1 r ± 12 - P σ 1 r ± 6 ² (1) = E 2 p P σ 2 r ± 12 - 2 P σ 2 r ± 6 ² (2) = K R r 12 - K A r 6 (3) where E 1 and E 2 are energies, σ 1 and σ 2 are distances, and K A and K R are constants with units necessary for the equalities above. a. Determine the SI units of K R and K A such that expression (3) makes sense. If the terms have units of energy (and they do), then we have [ K A ] = [ Jm 6 ] and [ K R ] = [ Jm 12 ] . b. Write the interatomic force F ( r ) associated with the energy expressed in the form (1). F ( r ) = - ∂V ∂r = 24 E 1 σ 1 p 2 P σ 1 r ± 13 - P σ 1 r ± 7 ² (4) c. Write the interatomic force F ( r ) associated with the energy expressed in the form (2).
Background image of page 1

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

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/18/2011 for the course ENG 045 taught by Professor Jensen during the Fall '11 term at UC Davis.

Page1 / 3

ENG045_HW.3.SOLNS - DATE: DUE: ENG45, Solution to homework...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online