[3dem] lambda
Ramanathan Natesh
r.natesh at mail.cryst.bbk.ac.uk
Thu Nov 15 10:17:43 PST 2007
Hi All,
Could anyone point me to a reference or show me how do we get from
classical formula for wavelength
lambda = h/sqrt(2meV) to lambda = 12.398/sqrt[kV*(1022+kV)]
that is used in SPIDER glossary
http://www.wadsworth.org/spider_doc/spider/docs/glossary.html#Lambda
m=mass 9.11 x 10^-31 Kg; e=electron charge 1.6 x 10^-19 C
h= 6.62 x 10^-34 J*sec V=voltage in volts
kV=kilo Volts.
eg: for 120 kV I get lambda = 0.03539 using classic formula but
I get lambda = 0.03349 from formula in SPIDER
glossary. Though the variation in 3rd decimal may/may not be
significant.
thanks in advance,
natesh.
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