<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body text="#000000" bgcolor="#ffffff">
Dear PW users,<br>
<br>
I calculated the dielectric function of (3,3) Carbon nanotube
(CNT). However, the results for only interband contribution has the
features of intraband contribution! Attached figures show the
results of parallel polarization compared with wien2k (a FP-LAPW
software). Using "intrasmear = 0", the direct result of epsi.dat
should gives out only interband contributions, while epsr.dat is
added by "omega_p^2/omega^2" to get the interband contributions
only. And omega_p is obtained as <b>3.5679eV</b> by fitting the
difference of data with intrasmear=0 and intrasmear=0.1 using Drude
model "\epsilon_{intra}=1- omega_p^2/(omega^2+i*omega*intrasmear)".
How to understand this?<br>
<br>
Another problem is, fitted omega_p = 3.5679eV. This is far from
the result given by wien2k, 24.5eV! Which one is more reasonable?
And why?<br>
<br>
Can anyone help me? Thanks in advance!<br>
<br>
Best wishes,<br>
<br>
Liu Gui-Bin<br>
Dept. of Physics, The University of Hong Kong<br>
<br>
---------------input file for epsilon.x----------<br>
&inputpp<br>
outdir='./work'<br>
prefix='cnt33'<br>
calculation='eps'<br>
/<br>
&energy_grid<br>
smeartype='gauss'<br>
intersmear=0.1d0<br>
intrasmear=0d0<br>
wmax=30d0<br>
wmin=0d0<br>
nw=2000<br>
shift=0d0<br>
/<br>
----------------------------------------------------------<br>
</body>
</html>