Tami Spector (USF) on "The Molecular Elusive" at a Berkeley LASER http://www.scaruffi.com/leonardo/feb2015b.html

1. The$Molecular$Elusive$
Time$and$Aesthe5cs$in$Chemistry$
$
$
$
$
$
Tami$I.$Spector$
University$of$San$Francisco,$Dept.$of$Chemistry$
(spector@usfca.edu)$

2. “The%huge%variety%of%chemical%species,%types%of%
reac6ons,%and%the%accompanying%poten6al%energy%
surfaces%involved%means%that%the%6mescale%over%which%
chemical%reac6ons%occur%covers%many%orders%of%
magnitude”%(Claire%Vallance,%“Reac6on%Kine6cs”)%$

3. Very$Slow$Reac5ons$$

4. Cai$Guo$Qiang,!Restrained!Violence:!Rainbow:!Project!for!Extraterrestrials!No.!
25,%2002%Johannesburg%Biennial,%Johannesburg,%South%Africa%%
Gunpowder:%5%kg,%fuse:%500%meters,%Photo:%Kochi%Watari%$$
%
Extremely$Fast$Reac5ons$

5. Reac5ons$That$Occur$on$a$Percep5ble$Time$Scale$
BriggsNRauscher%“Oscilla6ng%Clock%Reac6on”%

6. • Reac6ons%materially%appear%to%go%from%star6ng%material%to%
product%
• Along%the%path%from%star6ng%material%to%product%various%
transient%(very%short%lived)%molecular%species%are%formed%
%
Oxida6on%of%Iron%to%Fe%(II)%
Oxida6on%of%Fe%(II)%%to%Fe%(III)%in%presence%of%water%
Fe%III%combine%with%Oxygen%to%form%Fe%(III)%oxide%
Fe%(III)%oxide)%is%hydrated%with%water%

7. • Dis5nc5on$between$slow$and$fast$reac5ons$is$based$on$how$oNen$
the$reac5ons$occur$on$a$molecular$level,$not$how$quickly$$
• Given$enough$energy,$all$reac5ons$on$the$molecular$level$proceed$
very$quickly$through$transient$molecular$species$
• Time$in$Transi5on$State:$femtosecond$(fs)$5me$scale$(10T15$sec)$
• Time$as$Intermediate$(Minima):$(10T10$T$10T6$sec)$$

8. Stable$(low$energy)$/Persistent$(long$life5me)$$

9. “The$transi5on$state$is$neither$one$thing,$
namely,$chemical$reagents,$nor$the$other,$
reac5on$products.$Instead$it$illustrates$the$
mys5cal$event$of$transTsubstan5a5on.”$
%%
(John%C.%%Polanyi%and%Ahmed%H.%Zewail,%“Direct%Observa6on%of%the%Transi6on%
State,”%1995)%
%
The$Transi5on$State$(fs$5mescale)*$$
*One%femtosecond%is%10N15%seconds,%that%is,%0.000000000000001%seconds,%which%is%to%a%
second%as%a%second%is%to%32%million%years.%%

10. “Cyclobutadiene,%(CH)4,%is%the%Mona%Lisa%of%organic%chemistry%in%
its%ability%to%elicit%wonder,%s6mulate%the%imagina6on,%and%
challenge%interpre6ve%ins6ncts.%No%other%organic%compound%
combines%such$a$flee5ng$existence$and%so%many%different%
syntheses,%with%such%a%propensity%for%different%chemical%
reac6ons,%and%with%the%variety%of%calcula6ons%of%its%structure.”%%
(Donald%J.%Cram,%et!al.!“The%Taming%of%Cyclobutadiene”,%1991)%
%
%
The$Intermediate$(10T10$T$10T6$sec$5mescale)$$
$
Fe
CO
CO
OC
Ce(IV)
E

11. $
Femtochemistry%has%fundamentally%changed%our%view%of%
chemical%reac6ons.%From%a%phenomenon%described%in%
rela6vely%vague%metaphors%such%as%'ac6va6on'%and%
'transi6on%state',%we%can%now%see%the%movements%of%
individual%atoms%as%we%imagine%them.%They%are%no%
longer%invisible.%
%
%
%
%
%
%
%
Press%release%for$Ahmed%Zewail,%awarded%the%1999%Nobel%Prize%in%Chemistry%“For!his!
studies!of!the!transi?on!states!of!chemical!reac?ons!using!femtosecond!spectroscopy”$

12. ...it%is%the%molecules,%and%only%the%molecules,%for%which%
claims%of%beauty%and%ar6s6c%crea6vity%are%jus6fied,%no%
mader%what%sensual%quali6es%the%corresponding%
materials%have. %
%(Joachim%Schummer,%“Aesthe6cs%of%Chemical%Products,”%2003)%

13. The$Transi5on$State$$$

14. The$Transi5on$State$$$
Time%Snapshot%

15. The$Transi5on$State$$$
Time%Snapshot%
Twisted%TS%
PE%Surface%

16. Time%Snapshot%
Twisted%TS%
PE%Surface%
“Transi6on%state%theory%allows%the%chemist%in%a%sense%to%visualize%?me!itself…6me%
that%is%completely%tethered%to%space”%(Stephen%Weininger,%2000)%
%
Aesthe5cs$of$Transient$Molecular$Systems$
%

17. “To%be%concentrated%is%to%be%symbolically%powerful”(Barbara%Maria%Stafford,%Echo!
Objects,%2007)%
Sta5c$Structures$of$Transi5on$States$and$Intermediates$
Compress$5me,$space$and$energy$into$a$single$structure$
Aesthe5cs$of$Transient$Molecular$Systems$
%

18. %.30!Bullet!Piercing!an!Apple%(Harold%Edgerton,%1964)%
“…we%may%also%think%of%sta5c$pictures$which%only%implicitly$have$a$narra5ve$
func5on.%That%is,%where%a%frozen%scene%in%a%tacit%ac6on%sequence%has%been%
chosen,%from%which%what%has%preceded%and%will%follow%has%to%be%inferred%by%
the%beholder.”%(Michael%Ranta,%“Narra6vity%and%Time%in%Sta6c%Pictures”,%2001)%%
%

19. “In%the%experience%of%any%change%we%may%iden6fy%a%
par6cularly%salient%point,%such%as%the%moment%a%longN
distance%runner%crosses%the%finishing%line.%We%might%
represent%this%as%a%6meNslice%of%the%ac6on,%but%in%fact%(since%
we%perceived%it)%it%has%a%nonNzero%dura6on.%This,%then,%is%
what%sta6c%images%are%capable%of%depic6ng:%specious!
instants!which%are%parts%of%a%larger%movement%represented%
by%the%image.%Images%can%thus%represent%a%movement%by%
depic6ng%perceptually%minimum%parts%of%it.”%(“Time%and%the%
Sta6c%Image,”%Robin%Le%Poidevin,%1997)%%
%
Instants$have$no$dura5on$and$therefore$are$impercep5ble$
Specious$instant$=$the$smallest$perceivable$part$of$an$instant$
Timeframes$of$Transi5on$States$and$Intermediates$=$specious$instants$
Depic5ons$of$Transi5on$States$and$Intermediates$express$the$
impercep5bility$of$5me$
%

20. Fin