View source for Mostafa El-Sayed

{{short description|Egyptian chemist}}
{{Infobox scientist
| name              = Mostafa El-Sayed
| image             = MAE Profile I 031516.jpg
| caption           = El-Sayed in March 2016
| birth_date        = {{birth date and age|df=yes|1933|5|8}}
| birth_place       = [[Zifta]], [[Gharbia Governorate|Gharbia]], [[Kingdom of Egypt]]
| nationality       = [[Egypt|Egyptian]]
| alma_mater        = [[Ain Shams University]] <br> [[Florida State University]]
| doctoral_advisor  = [[Michael Kasha]]<ref>{{cite journal |last1=El-Sayed |first1=Mostafa |title=Michael Kasha - Editorial, Biographical Sketch, Summary of Research Contributions, Research Associates, and Publications list |journal=Journal of Physical Chemistry |date=December 1, 1991 |volume=95 |issue=25 |page=10215-10220 |doi=10.1021/j100178a001 |url=https://pubs.acs.org/doi/abs/10.1021/j100178a001 |access-date=5 February 2021|url-access=subscription }}</ref>
| education         = 
| known_for         = [[Nanotechnology]]<br>[[Spectroscopy]]<br>[[El-Sayed rule]]
| field             = [[Chemical physicist]]
| work_institution  = [[Georgia Institute of Technology]]<br>[[Harvard University]]<br>[[University of California at Los Angeles]]
| awards            = [[King Faisal International Prize]] 1990<br />[[Irving Langmuir Award]] 2002<br />[[National Medal of Science]] 2007 <br /> [[Glenn T. Seaborg Medal]] 2009<br /> [[Priestley Medal]] 2016
}}

'''Mostafa A. El-Sayed''' ({{langx|ar|مصطفى السيد}}) is an [[Egyptian-American]] physical chemist, nanoscience researcher, member of the [[United States National Academy of Sciences|National Academy of Sciences]] and [[National Medal of Science|US National Medal of Science]] laureate. He is known for the spectroscopy rule named after him, the ''El-Sayed rule''.<ref>{{GoldBookRef |title=El-Sayed rules |file=ET07369 }}</ref><ref>{{cite book|author1=David Oxtoby |author2=H. Gillis |author3=Alan Campion |title=Principles of Modern Chemistry|date=2007|publisher=Cengage Learning|isbn=9780534493660|page=990|edition=6|url=https://books.google.com/books?id=fJWpg4ZJ2esC&q=El-Sayed%27s+rule&pg=PA990}}</ref><ref>{{cite web|title=Prof. El-Sayed is in 2017 highly cited researchers list|url=http://www.ldl.gatech.edu/content/prof-el-sayed-2017-highly-cited-researchers-list-0}}</ref>

== Early life and academic career ==

El-Sayed was born in Zifta, Egypt and spent his early life in Cairo. He earned his [[Bachelor of Science|B.Sc.]] in chemistry from [[Ain Shams University]] Faculty of Science, [[Cairo]] in 1953.<ref>[http://www.chem.unl.edu/el_sayed_desc.html He applied for graduate school in the United States and emigrated there. Mostafa Amr El-Sayed]</ref> El-Sayed earned his doctoral degree in chemistry from [[Florida State University]] working with [[Michael Kasha]], the last student of the legendary [[G. N. Lewis]].{{cn|date=August 2017}} While attending graduate school he met and married Janice Jones, his wife of 48 years. He spent time as a post-doctoral researcher at [[Harvard University]], [[Yale University]] and the [[California Institute of Technology]] before joining the faculty of the [[University of California at Los Angeles]] in 1961. In 1994, he retired from UCLA and accepted the position of Julius Brown Chair and Regents Professor of Chemistry and Biochemistry at the [[Georgia Institute of Technology]]. He led the [http://www.ldl.gatech.edu/ Laser Dynamics Lab] there until his full retirement in 2020.

El-Sayed is a former editor-in-chief of the ''[[Journal of Physical Chemistry]]'' (1980–2004).<ref>{{cite news|title=El-Sayed, Mostafa A.|url=http://www.bibalex.org/cssp/Speakers/SpeakersDetails.aspx?ID=1|archive-url=https://web.archive.org/web/20110120025039/http://www.bibalex.org/cssp/Speakers/SpeakersDetails.aspx?ID=1|url-status=dead|archive-date=January 20, 2011|access-date=20 February 2015|publisher=bibalex.org}}</ref><ref>[[Chemical & Engineering News]] Vol. 86 No. 35, 1 Sept. 2008, "Chemists Receive Top Awards", p. 10]</ref>

== Research ==
[[File:Mostapha with 2 students.JPG|thumb|right|Prof. El-Sayed with two students, 2008]]
El-Sayed's research interests include the use of [[steady-state]] and [[ultra fast laser spectroscopy]] to understand relaxation, transport and conversion of energy in [[molecules]], in [[solids]], in [[photosynthetic]] systems, semiconductor [[quantum dots]] and metal [[nanostructures]]. The El-Sayed group has also been involved in the development of new techniques such as magnetophotonic selection, picosecond [[Raman spectroscopy]] and phosphorescence microwave double resonance spectroscopy. A major focus of his lab is currently on the optical and chemical properties of [[noble metal]] [[nanoparticles]] and their applications in nano[[catalysis]], [[nanophotonics]] and [[nanomedicine]]. His lab is known for the development of the [[gold nanorods|gold nanorod]] technology. As of 2021, El-Sayed has produced over 1200 publications in refereed journals in the areas of [[spectroscopy]], [[molecular dynamics]] and [[nanoscience]], with over 130,000 citations.<ref>{{cite web |title="Mostafa A. El-Sayed" |url=https://scholar.google.com/citations?user=BMpDLscAAAAJ&hl=en&oi=ao |website=Google Scholar |access-date=5 February 2021}}</ref>

== Honors ==

For his work in the area of applying [[laser]] spectroscopic techniques to study of properties and behavior on the [[Nanoscopic scale|nanoscale]], El-Sayed was elected to the [[United States National Academy of Sciences|National Academy of Sciences]] in 1980. In 1989 he received the [[Tolman Award]], and in 2002, he won the [[Irving Langmuir Award]] in Chemical Physics. He has been the recipient of the 1990 [[King Faisal International Prize]] ("Arabian Nobel Prize") in Sciences, [[Georgia Tech]]'s highest award, "The Class of 1943 Distinguished Professor", an honorary doctorate of philosophy from the [[Hebrew University]],  and several other awards including some from the different [[American Chemical Society]] local sections. He was a [[Sherman Fairchild]] Distinguished Scholar at the [[California Institute of Technology]] and an Alexander von Humboldt Senior U.S. Scientist Awardee. He served as editor-in-chief of the ''[[Journal of Physical Chemistry]]'' from 1980 to 2004 and has also served as the U.S. editor of the ''International Reviews in Physical Chemistry''. He is a Fellow of the [[American Academy of Arts and Sciences]], a member of the [[American Physical Society]], the [[American Association for the Advancement of Science]] and the [[Third World Academy of Science]]. Mostafa El-Sayed was awarded the 2007 US [[National Medal of Science]] "for his seminal and creative contributions to our understanding of the [[Electricity|electronic]] and [[optical]] properties of [[nanomaterials]] and to their applications in nano[[catalysis]] and [[nanomedicine]], for his [[humanitarian]] efforts of exchange among countries and for his role in developing the scientific leadership of tomorrow."<ref>{{Cite web|url=https://www.nsf.gov/od/nms/recip_details.cfm?recip_id=5300000000445|title=The President's National Medal of Science: Recipient Details {{!}} NSF - National Science Foundation|website=www.nsf.gov|language=en|access-date=2017-10-27}}</ref> Mostafa was also announced to be the recipient of the 2009 [[Ahmed Zewail]] prize in molecular sciences. In 2011, he was listed #17 in Thomson-Reuters listing of the Top Chemists of the Past Decade.<ref>[http://www.chemistry.gatech.edu/faculty/El-Sayed/ Mostafa El-Sayed] College of Sciences, Georgia Institute of Technology. Accessed 27 November 2014</ref>  Professor El-Sayed also received the 2016 [[Priestley Medal]], the [[American Chemical Society]]’s highest honor, for his decades-long contributions to chemistry.<ref>{{Cite web|url=http://cen.acs.org/articles/93/web/2015/06/Mostafa-El-Sayed-Wins-Priestley.html|title=Mostafa El-Sayed Wins Priestley Medal {{!}} Chemical & Engineering News|last=Jacoby|first=Mitch|website=cen.acs.org|access-date=2016-08-01}}</ref>

== The El-Sayed rule ==

{{rquote|quote=The rate of intersystem crossing is relatively large if the radiationless transition involves a change of orbital type.|author=Mostafa El-Sayed|source=<ref>{{cite journal |last1=Braslavsky |first1=S. E. |title=Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006) |journal=Pure and Applied Chemistry |date=1 January 2007 |volume=79 |issue=3 |pages=293–465 |doi=10.1351/pac200779030293|s2cid=96601716 |doi-access=free }}</ref>}}

This rule pertains to [[phosphorescence]] and similar phenomena.  Electrons vibrate and resonate around molecules in different [[Normal mode|modes]] ([[electronic state]]), usually depending on the energy of the system of electrons.  This law states that constant-energy flipping between two electronic states happens more readily when the vibrations of the electrons are preserved during the flip: any change in the [[electron spin|spin]] of an electron is compensated by a change in its orbital motion ([[spin-orbit coupling]]).

[[Intersystem crossing]] (ISC) is a photophysical process involving an isoenergetic radiationless transition between two [[electronic state]]s having different multiplicities. It often results in a vibrationally excited molecular entity in the lower electronic state, which then usually decays to its lowest [[molecular vibration]]al level. ISC is forbidden by rules of conservation of [[angular momentum]]. As a consequence, ISC generally occurs on very long time scales. However, the El-Sayed rule states that the rate of intersystem crossing, e.g. from the lowest [[singlet state]] to the triplet manifold, is relatively large if the radiationless transition involves a change of [[molecular orbital]] type.<ref>{{cite journal |last1=Baba |first1=Masaaki |title=Intersystem Crossing in the 1npi* and 1pipi* States |journal=Journal of Physical Chemistry A |date=March 14, 2011 |volume=115 |issue=34 |pages=9514–9519 |doi=10.1021/jp111892y |pmid=21401029 |bibcode=2011JPCA..115.9514B |url=https://pubs.acs.org/doi/pdf/10.1021/jp111892y |access-date=5 February 2021|url-access=subscription }}</ref><ref>{{cite journal |last1=Soto |first1=Juan |last2=Otero |first2=Juan O. |title=Conservation of El-Sayed's Rules in the Photolysis of Phenyl Azide: Two Independent Decomposition Doorways for Alternate Direct Formation of Triplet and Singlet Phenylnitrene |journal=Journal of Physical Chemistry A |date=October 1, 2019 |volume=123 |issue=42 |pages=9053–9060 |doi=10.1021/acs.jpca.9b06915 |pmid=31573200 |bibcode=2019JPCA..123.9053S |s2cid=203624906 |url=https://pubs.acs.org/doi/10.1021/acs.jpca.9b06915 |access-date=5 February 2021|url-access=subscription }}</ref> For example, a (π,π*) singlet could transition to a (n,π*) [[triplet state]], but not to a (π,π*) triplet state and vice versa. Formulated by El-Sayed in the 1960s, this rule found in most [[photochemistry]] textbooks as well as the [[IUPAC]] [[Gold Book]].<ref>{{cite book |last1=McNaught |first1=A.D. |last2=Wilkinson |first2=A. |title=IUPAC Compendium of Chemical Terminology (the "Gold Book") |date=1997 |publisher=Blackwell Scientific Publications |location=Oxford |isbn=0-9678550-9-8 |page=331 |edition=2nd |url=https://goldbook.iupac.org/terms/view/ET07369 |access-date=5 February 2021}}</ref> The rule is useful in understanding [[phosphorescence]], vibrational relaxation, [[intersystem crossing]], [[Internal conversion (chemistry)|internal conversion]] and lifetimes of excited states in molecules.

== Notes ==

{{reflist}}

== References ==
* El-Sayed, M.A., Acc. Chem. Res. 1968,1,8.
* Lower, S.K.; El-Sayed, M.A., Chem. Rev. 1966,66,199
* Mostafa Amr El-Sayed (8 May 1933 – Egyptian-American, b. Zifta, Egypt)
* Biographical References: McMurray, Emily J. (ed.), Notable Twientieth-Century Scientists, Gale Research, Inc.: New York, 1995.

== External links ==
{{Sister project links|Mostafa El-Sayed|wikt=no|n=no|s=no|b=no|voy=no|v=no}}
{{Scholia|author}}
* [http://www.chemistry.gatech.edu/faculty/El-Sayed/ Faculty web page at Georgia Tech]
* [http://ldl.gatech.edu/ Laser Dynamics Lab] at Georgia Tech
* [http://www.bizjournals.com/atlanta/stories/2008/08/25/daily59.html?surround=lfn President Bush to laud Georgia Tech’s Mostafa El-Sayed]
* [https://web.archive.org/web/20110525080621/http://www.us4arabs.com/content/view/952/31 Mostafa El-Sayed praised for contributions to nanotechnology]

{{Winners of the National Medal of Science|chemistry}}
{{Portal bar|Biography|Islam|Chemistry|Science}}
{{Authority control}}

{{DEFAULTSORT:Sayed, Mostafa}}
[[Category:Biochemists]]
[[Category:Egyptian chemists]]
[[Category:Egyptian Muslims]]
[[Category:American Muslims]]
[[Category:Egyptian inventors]]
[[Category:Egyptian emigrants to the United States]]
[[Category:Harvard University staff]]
[[Category:Members of the United States National Academy of Sciences]]
[[Category:Florida State University alumni]]
[[Category:Georgia Tech faculty]]
[[Category:Living people]]
[[Category:1933 births]]
[[Category:National Medal of Science laureates]]
[[Category:Ain Shams University alumni]]
[[Category:American physical chemists]]
[[Category:Fellows of the American Physical Society]]
[[Category:Arab chemists]]