Citation
Leighton, Robert B (1947) The vibrational spectrum of a monatomic facecentered cubic crystal lattice. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd01092004101503
Abstract
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The equations of motion of the atoms of a facecentered, cubic crystal lattice are written, assuming central, Hooke's Law forces between each atom and its eighteen nearest neighbors, and the secular determinant defining the normal frequencies is obtained. This determinant is written as a product of third order determinant. The properties of the roots of the secular determinant are discussed, and it is shown that the surfaces of constant frequency have the symmetry properties (in reciprocalvector space) of a bodycentered cubic lattice. This fact is used to simplify the computation of the distribution of the normal frequencies. The frequency spectrum is found by actually modeling the constant frequency surfaces in plaster of Paris and measuring the volumes enclosed between successive surfaces. The frequency spectrum so obtained is used in the evaluation of the specific heat of a general crystal of the type treated, and numerical values are presented for the element silver. The present theory (that of Born and von Karman), is in much better agreement with the experimental values for temperatures below 100[degrees]k than is the Debye theory. Certain anomalies in the specific heat curves of silver and potassium chloride at temperatures below 10[degrees]K are not explicable in terms of the atomic model that is used.
Item Type:  Thesis (Dissertation (Ph.D.)) 

Degree Grantor:  California Institute of Technology 
Division:  Physics, Mathematics and Astronomy 
Major Option:  Physics 
Thesis Availability:  Public (worldwide access) 
Research Advisor(s): 

Thesis Committee: 

Defense Date:  1 January 1947 
Record Number:  CaltechETD:etd01092004101503 
Persistent URL:  http://resolver.caltech.edu/CaltechETD:etd01092004101503 
Default Usage Policy:  No commercial reproduction, distribution, display or performance rights in this work are provided. 
ID Code:  77 
Collection:  CaltechTHESIS 
Deposited By:  Imported from ETDdb 
Deposited On:  12 Jan 2004 
Last Modified:  26 Dec 2012 02:27 
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