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CONCEPTS AND METHODS OF 2D
INFRARED SPECTROSCOPY
2D infrared (IR) spectroscopy is a cutting-edge technique, with applications in
subjectsasdiverseastheenergysciences,biophysicsandphysicalchemistry.This
bookintroducestheessentialconceptsof2DIRspectroscopystep-by-steptobuild
anintuitiveandin-depthunderstandingofthemethod.
Taking a unique approach, this book outlines the mathematical formalism in a
simple manner, examines the design considerations for implementing the meth-
ods in the laboratory, and contains working computer code to simulate 2D IR
spectra and exercises to illustrate the concepts involved. Readers will learn how
to accurately interpret 2D IR spectra, design their own spectrometer and invent
their own pulse sequences. It is an excellent starting point for graduate stu-
dents and researchers new to this exciting field. Computer codes and answers
to the exercises can be downloaded from the authors’ website, available at
www.cambridge.org/9781107000056.
PETER HAMM is a Professor at the Institute of Physical Chemistry, University
ofZurich.
MARTIN ZANNI is Meloche-Bascom Professor in the Department of Chemistry,
UniversityofWisconsin-Madison.
They specialize in using 2D IR spectroscopy to study molecular structures and
dynamics.
CONCEPTS AND METHODS OF 2D
INFRARED SPECTROSCOPY
PETER HAMM
UniversityofZurich
and
MARTIN ZANNI
UniversityofWisconsin-Madison
CAMBRIDGE UNIVERSITY PRESS
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Singapore,SãoPaulo,Delhi,Tokyo,MexicoCity
CambridgeUniversityPress
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PublishedintheUnitedStatesofAmericabyCambridgeUniversityPress,NewYork
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Informationonthistitle:www.cambridge.org/9781107000056
(cid:2)c P.HammandM.Zanni2011
Thispublicationisincopyright.Subjecttostatutoryexception
andtotheprovisionsofrelevantcollectivelicensingagreements,
noreproductionofanypartmaytakeplacewithoutthewritten
permissionofCambridgeUniversityPress.
Firstpublished2011
PrintedintheUnitedKingdomattheUniversityPress,Cambridge
AcatalogrecordforthispublicationisavailablefromtheBritishLibrary
LibraryofCongressCataloginginPublicationdata
Hamm,Peter,1966–
Conceptsandmethodsof2dinfraredspectroscopy/PeterHamm
andMartinT.Zanni.
p. cm.
Includesbibliographicalreferencesandindex.
ISBN978-1-107-00005-6
1. Infraredspectra. I. Zanni,MartinT. II. Title.
QC457.H35 2011
(cid:3)
543.57–dc22
2010041962
ISBN978-1-107-00005-6Hardback
Additionalresourcesforthispublicationatwww.cambridge.org/9781107000056
CambridgeUniversityPresshasnoresponsibilityforthepersistenceor
accuracyofURLsforexternalorthird-partyinternetwebsitesreferredto
inthispublication,anddoesnotguaranteethatanycontentonsuch
websitesis,orwillremain,accurateorappropriate.
DedicatedtoRobinM.Hochstrasser.
Weappreciatethehelpofourstudents,postdoctoralresearchers,
colleagues,mentorsandfamilies.
Contents
1 Introduction page1
1.1 Studyingmolecularstructurewith2DIRspectroscopy 3
1.2 Structuraldistributionsandinhomogeneousbroadening 10
1.3 Studyingstructuraldynamicswith2DIRspectroscopy 12
1.4 Timedomain2DIRspectroscopy 14
Exercises 16
2 Designingmultiplepulseexperiments 18
2.1 Eigenstates,coherencesandtheemittedfield 18
2.2 Blochvectorsandmolecularensembles 23
2.3 Bloch vectors are a graphical representation of the density
matrix 27
2.4 MultiplepathwaysvisualizedwithFeynmandiagrams 31
2.5 Whatisabsorption? 37
2.6 Designingmulti-pulseexperiments 38
2.7 Selectingpathwaysbyphasematching 42
2.8 Selectingpathwaysbyphasecycling 44
2.9 DoublesidedFeynmandiagrams:Rules 46
Exercises 47
3 Mukamelianorperturbativeexpansionofthedensitymatrix 48
3.1 Densitymatrix 48
3.2 Timedependentperturbationtheory 52
Exercises 60
4 Basicsof2DIRspectroscopy 61
4.1 Linearspectroscopy 61
4.2 Third-orderresponsefunctions 65
4.3 Timedomain2DIRspectroscopy 69
vii
viii Contents
4.4 Frequencydomain2DIRspectroscopy 82
4.5 Transientpump–probespectroscopy 84
Exercises 86
5 Polarizationcontrol 88
5.1 Usingpolarizationtomanipulatethemolecularresponse 88
5.2 Diagonalpeak,norotations 92
5.3 Cross-peaksandorientationsofcoupledtransitiondipoles 93
5.4 Combiningpulsepolarizations:Eliminatingdiagonalpeaks 99
5.5 Including(orexcluding)rotationalmotions 100
5.6 Polarizationconditionsforhigher-orderpulsesequences 106
Exercises 108
6 Molecularcouplings 109
6.1 Vibrationalexcitons 109
6.2 Spectroscopyofacoupleddimer 114
6.3 Extendedexcitonsinregularstructures 120
6.4 Isotopelabeling 128
6.5 Localmodetransitiondipoles 133
6.6 Calculationofcouplingconstants 134
6.7 Localversusnormalmodes 137
6.8 Fermiresonance 140
Exercises 142
7 2DIRlineshapes 145
7.1 Microscopictheoryofdephasing 145
7.2 Correlationfunctions 149
7.3 Homogeneousandinhomogeneousdynamics 152
7.4 Nonlinearresponse 155
7.5 Photonechopeakshiftexperiments 161
Exercises 164
8 Dynamiccross-peaks 166
8.1 Populationtransfer 166
8.2 Dynamicresponsefunctions 172
8.3 Chemicalexchange 174
9 Experimentaldesigns,datacollectionandprocessing 176
9.1 Frequencydomainspectrometerdesigns 176
9.2 Experimental considerations for impulsive spectrometer
designs 180
9.3 Capabilitiesmadepossiblebyphasecontrol 191
