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Unformatted text preview: Quiz 5C 2 DL See Grading:  
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famin llaIlle 1. Consider a system made. of 4 atoms all at. rest. on. the same plane. T hey are arranged in a closed packed
structure {see ﬁgure. below] and the}r are interacting with each other via the LennardJones potential (see
ﬁgure below}. The diameter of the atoms is or t 3 X ill—mm and the depth of the potential is e = 8 X 10—21.}.
The distanee between nearest neighbors is 1.126. and between not. nearest neighbors is 1.70. 2 1
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V12 How many bonds between nearest. neighbors are there in the system"? Clearly show where they are with
a sketch. 1'; loot/L615 C ") (b) How many bonds between not nearest neighbors are there in the system? Clearly show where they are
with a sketeh .1 mi (W0 Find the bond energv of the system (show your work). E5 1 3‘ @th‘r = *7 (r 0+ it 0.62.)!“ 5.6g 520:.) H > Mt/ 52.1
._ 13.x? 3(ch lo I PLEASE TURN PAGE ‘2. You are given the plot for the Lennard~301ms potential shown below and you are told that it (leseribes the
interaction between two atoms. You are also told that the system made of the two atoms has Ego: : —().7é. (a) Are the two atoms bonded? Explain Briefly. ,_ g r r /(
.— r—h ‘ L w M  w{ (M ﬁtw
Yes) W80“ m ‘3' “ta C the»; email ‘WW (1)] Find the maximum and the minimum separation between the atoms [i.e. rm” and rmm), dearly
explaining how you got them. Yhtw 2’ .2 r Fl:va \( iéol )
wwi “I Maht (:1 To?
Now suppose you add 0.26 to the Em of the system of UM) atoms. (a) Have. you broken the bond between the two atoms? Explain brieﬂy _—.——. VD.) R( [St 18 311i 2163th (b) What are Tmm and rm” now? limit/t: «LOW YMyg/l.°ac3) (e) “Eben the distance between the two atoms is Tm“; and they are momentarily at rest. what is the
potential energy of the system? (Show your Work!) ‘4; C30 Q; 2 P21)? 1 ’ r‘ legl :0 ...
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 Spring '08
 Taylor

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