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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><STRONG><SPAN
style="FONT-FAMILY: Arial"><FONT size=3>Poštovani,</FONT></SPAN></STRONG><SPAN
style="FONT-FAMILY: Arial"><BR><STRONG><FONT size=3>podsjećamo Vas na <SPAN
style="COLOR: red">današnji</SPAN> seminar na</FONT></STRONG></SPAN><SPAN
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za fiziku u <SPAN style="COLOR: red">15:00 </SPAN><SPAN
style="COLOR: black">sati:</SPAN></SPAN></STRONG></DIV>
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<P style="MARGIN: 3.1pt 0cm; TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 'Century Gothic'"><IMG height=32
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<P class=MsoNormal style="MARGIN: 3pt 0cm; TEXT-ALIGN: center"
align=center><B style="mso-bidi-font-weight: normal"><SPAN
style="COLOR: #5f5f5f; FONT-FAMILY: 'Century Gothic'">Institut za fiziku,
Bijenička cesta 46,<o:p></o:p></SPAN></B></P>
<P class=MsoNormal style="MARGIN: 3pt 0cm; TEXT-ALIGN: center"
align=center><B style="mso-bidi-font-weight: normal"><SPAN
style="COLOR: #5f5f5f; FONT-FAMILY: 'Century Gothic'">predavaonica u
zgradi Mladen Paić<o:p></o:p></SPAN></B></P>
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align=center><B style="mso-bidi-font-weight: normal"><SPAN
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<P style="MARGIN: 3.1pt 0cm; TEXT-ALIGN: center" align=center><B
style="mso-bidi-font-weight: normal"><SPAN
style="FONT-SIZE: 14pt; COLOR: #993300; FONT-FAMILY: 'Century Gothic'">u
ponedjeljak, 19. prosinca 2011. u 15:00 sati</SPAN></B><SPAN
style="FONT-FAMILY: 'Century Gothic'"><o:p></o:p></SPAN></P></TD></TR>
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<TD
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<P
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face="Arial Unicode MS"> <o:p></o:p></FONT></SPAN></B></P>
<P
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align=center><FONT face="Arial Unicode MS"><B><SPAN
style="FONT-SIZE: 16pt; COLOR: #55913c; mso-bidi-font-size: 14.0pt">Transient
Excitons on Metals: Fact or Fiction?</SPAN></B><B><SPAN
style="FONT-SIZE: 16pt; COLOR: #55913c; FONT-FAMILY: 'Century Gothic'; LETTER-SPACING: -0.7pt; mso-bidi-font-size: 12.0pt"><o:p></o:p></SPAN></B></FONT></P></TD></TR>
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<P
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align=center><FONT face="Arial Unicode MS"><SPAN class=object><B><SPAN
style="FONT-SIZE: 14pt; COLOR: black; mso-bidi-font-size: 12.0pt">Prof.
dr. Hrvoje Petek</SPAN></B></SPAN><B><SPAN
style="FONT-SIZE: 14pt; mso-bidi-font-size: 12.0pt"><o:p></o:p></SPAN></B></FONT></P></TD></TR>
<TR>
<TD
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<P
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align=center><FONT face="Arial Unicode MS"><B><SPAN
style="FONT-SIZE: 13pt; mso-bidi-font-size: 8.0pt">Department of Physics
and Astronomy, University of Pittsburgh, USA</SPAN></B><B
style="mso-bidi-font-weight: normal"><SPAN lang=EN-US
style="FONT-SIZE: 13pt; mso-bidi-font-size: 12.0pt; mso-ansi-language: EN-US"><o:p></o:p></SPAN></B></FONT></P>
<P style="MARGIN: 5.95pt 0cm 0pt; TEXT-ALIGN: center"
align=center><B><I><SPAN
style="FONT-SIZE: 11pt; FONT-FAMILY: 'Century Gothic'; mso-bidi-font-size: 12.0pt">E-mail:</SPAN></I></B><SPAN
style="FONT-SIZE: 9pt; COLOR: #333333; mso-ansi-language: EN"><FONT
face="Arial Unicode MS"> </FONT></SPAN><B><I><SPAN lang=EN
style="FONT-SIZE: 11pt; COLOR: #333333; FONT-FAMILY: 'Century Gothic'; mso-bidi-font-size: 9.0pt; mso-ansi-language: EN"><A
href="mailto:petek@pitt.edu">petek@pitt.edu</A></SPAN></I></B><B><I><SPAN
lang=EN
style="FONT-SIZE: 11pt; FONT-FAMILY: 'Century Gothic'; mso-bidi-font-size: 12.0pt">
</SPAN></I></B><B><SPAN
style="FONT-SIZE: 11pt; COLOR: black; FONT-FAMILY: 'Century Gothic'; mso-bidi-font-size: 12.0pt"><o:p></o:p></SPAN></B></P></TD></TR>
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<P class=MsoBodyText
style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 18pt; TEXT-ALIGN: justify; mso-line-height-rule: exactly"><B><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Century Gothic'"> <o:p></o:p></SPAN></B></P>
<P class=MsoBodyText
style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 18pt; TEXT-ALIGN: justify; mso-line-height-rule: exactly"><B><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Century Gothic'; mso-bidi-font-size: 8.0pt; mso-bidi-font-family: Tahoma">The
high electron density within metals screens the Coulomb interaction
efficiently on the length scale of interatomic distance and the time scale
of inverse plasma frequency, i.e., typically in the sub-femtosecond
regime.<SPAN style="mso-spacerun: yes"> </SPAN>Nevertheless,
transient excitonic interactions have been invoked in theoretical
descriptions of the renormalization of optical spectral density and hot
electron lifetimes in noble metals.<SPAN style="mso-spacerun: yes">
</SPAN>We explore the surface electronic structure of silver and copper
surfaces by energy, momentum, and time-resolved multiphoton
photoemission.<SPAN style="mso-spacerun: yes"> </SPAN>Features
observed in the near-resonant multi-photon photoemission spectra cannot be
understood from the joint density of preexisting occupied and unoccupied
states that are coupled by optical transitions and a Fermi Golden Rule
transition rate formalism, suggesting that quasiparticle correlations, for
example, transient excitonic interaction between photoexcited electron and
hole, as well as delayed formation of image potential states may affect
the transition amplitudes and quasiparticle lifetimes.<SPAN
style="mso-spacerun: yes"> </SPAN>Different behavior observed for
copper and silver surfaces suggest that the observed behavior may be a
manifestation of inefficient Coulomb screening leading to transient
excitonic interactions and the retarded formation of image potential
states that have been predicted theoretically by Gumhalter and
coworkers.</SPAN></B><B><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Century Gothic'"><o:p></o:p></SPAN></B></P>
<P class=MsoBodyText
style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 10pt; TEXT-ALIGN: justify; mso-line-height-rule: exactly"><B><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Century Gothic'"> <o:p></o:p></SPAN></B></P>
<P class=MsoBodyText
style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 10pt; TEXT-ALIGN: justify; mso-line-height-rule: exactly"><B><SPAN
style="FONT-SIZE: 11pt; COLOR: blue; FONT-FAMILY: 'Century Gothic'; mso-bidi-font-size: 12.0pt">http://www.physicsandastronomy.pitt.edu/people/hrvoje_petek<o:p></o:p></SPAN></B></P></TD></TR>
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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><B><SPAN
style="FONT-SIZE: 11pt; FONT-FAMILY: 'Century Gothic'; mso-bidi-font-size: 12.0pt"> <o:p></o:p></SPAN></B></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><B><SPAN
style="FONT-SIZE: 11pt; FONT-FAMILY: 'Century Gothic'; mso-bidi-font-size: 12.0pt">Voditelji
seminara IF-a: Vlasta Horvatić i Ivica
Živković</SPAN></B><o:p></o:p></P></TD></TR></TBODY></TABLE></SPAN></SPAN></STRONG></FONT></DIV></BODY></HTML>