Frontiers in Spectroscopy
Chemical Physics 8880.01 and 8808.02
Course Description: This course will provide
students with an overview of topics on the frontier of spectroscopic
research. It will exploit internationally renowned lecturers, as well
as outstanding OSU faculty, to cover topics ranging from very
fundamental to quite applied. General areas to be covered will include
fundamental characteristics of molecular quantum structure,
electromagnetics, new experimental techniques, remote sensing,
ultra-high sensitivity analytical techniques, astrophysical
applications, etc. It is planned that the course will be offered
multiple times, with topics and speakers varying with each
offering. The lecturers for the upcoming Winter quarter are listed
A feature of ChemPhys 8880 is a one hour "pre-lecture" discussion period led by an OSU faculty member. It is designed to help orient students to the readings, which they are expected to have read prior to the pre-lecture. Unless otherwise indicated, the pre-lecture will be held in 2136 Newman-Wolfrom at 5:30pm on the Tuesdays of the weeks with lectures.
Each topic will be covered by lectures on Wednesday and Friday
mornings, 9:35-10:55AM, in MP2015.
Thursdays discussions (for students only) will begin at 9:35-10:55AM
on Thursdays in MP2015.
Prerequisites: a previous spectroscopy course
at OSU in Chemistry or Physics or prior permission of the
Required Text: None; suggested articles for
reading will be supplied prior to the lecture on a given topic.
All readings and lecture notes
kept current on Carmen. If you are enrolled for Frontiers this semester, you
have your normal student login and password. If you are an advisor or
post-doc and would like access to the readings and notes, email Becky
Gregory, email@example.com, and she will arrange for a login and
password for this site.
List of speakers and dates scheduled:
January 28 - 5:30pm-6:30pm in 2136 Newman-Wolfrom - Pre-Lecture discussion by Walter Lempert
Readings for Azer Yalin lectures (access pdfs on Carmen):
1. A.P. Yalin, V. Surla, M. Butweiller, J.D. Williams "Detection of Sputtered Metals using Cavity Ring-Down Spectroscopy" Applied Optics 44, (30), pp. 6496-650 (2005)
2. Brian C. Lee, Azer P. Yalin, Alec Gallimore, Wensheng Huang and Hani Kamhawi "Real-Time Boron Nitride Erosion Measurements of the HiVHAc Thruster via Cavity Ring-Down Spectroscopy" IEPC-2013-119, 33rd International Electric Propulsion Conference (2013)
3. A.P. Yalin, R.N. Zare, C.O. Laux, C.H. Kruger "Spatial Profiles of N2+ Concentration in an Atmospheric Pressure Nitrogen Glow Discharge" Plasma Sources Science and Technology 11, (3), pp. 248-253 (2002)
4. C.L. Hagen, B.C. Lee, I.S. Franka, J. L. Rath, T.C. VandenBoer, J.M. Roberts, S.S. Brown and A. P. Yalin "Cavity Ring-Down Spectroscopy Sensor for Detection of Hydrogen Chloride" Atmos. Meas. Tech. Discuss., 6, 7217-7250 (2013)
5. Paul S. Johnston and Kevin K. Lehmann "Cavity enhanced absorption spectroscopy using a broadband prism cavity and a supercontinuum source" Optics Express Vol. 16 15013 (2008)
January 29-31 Azer Yalin, Colorado State University
- Lecture 1: Cavity Enhanced Spectroscopy for Trace Species and Plasma Measurements
-overview of cavity enhanced spectroscopy and cavity ring-down spectroscopy (CRDS)
-overview of applications
-cavity enhanced plasma measurements:
-CRDS of sputter products and plasma thrusters
-CRDS of atmospheric pressure plasmas
-cavity enhanced polarimetry for measurement of electric fields
- Lecture 2 (Student Session): Experimental Details of Cavity Ring-Down Spectroscopy (CRDS)
-pulsed versus c-w cavity ring-down spectroscopy (lineshape effects)
-stability of optical cavities (beam steering by plasma)
-mode matching of optical cavities
-power injection to cavity
-signal acquisition and fitting
-detection limits and Allan variance
- Lecture 3: Recent and Future Developments in Cavity Enhanced Spectroscopy
-prism retro-reflector cavities
-ultraviolet measurements (CaF2 prisms)
-mid-infrared measurements (QCLs)
-scattering measurements from buildup cavities (Raman and Thomson)
February 18 - 5:30pm-6:30pm in 2136 Newman-Wolfrom - Pre-Lecture discussion by Anne McCoy
Readings can be accessed on Carmen
February 19-21 Jon Hougen, NIST
- Lecture 1
Part 1, about 30 min.
What are we discussing and why?
Keywords for the "what" part of the lecture. The "why" will be added orally.
1. Selection rules for quantized motions versus propensity rules for non-quantized motions.
2. Large Amplitude Motions (LAMs) versus Small Amplitude Vibrations (SAVs), or slow motions versus fast motions, or small-quantum motions versus large-quantum motions.
3. Frequency-domain thinking (stationary-states) versus time-domain thinking (dynamics), or boundary-value differential equation problems versus initial-value differential equation problems, or many-significant-figure measurements versus few-significant-figure measurements.
4. The rapid convergence of Fourier series for treating rotatory LAMs (e.g., internal rotation) versus the slow convergence of power series for treating reciprocating (back-and-forth) LAMs (e.g., diatomic molecule vibrations, ammonia inversion).
5. The precision offered by tunneling Hamiltonians versus the chemical understanding offered by Hamiltonians with explicit potential functions.
6. The present CH3OH research project, with one LAM (= internal rotation of the CH3 group), and 11 SAVs (= bond stretches and bends).
7. Projected SAV frequencies along a steepest descent LAM path from saddle to minimum.
Part 2, half words, half equations, about 45 min.
What are the key quantum mechanical concepts needed to understand the methanol normal mode results along the internal rotation path = "the projected frequencies"?
How are these concepts described mathematically?
8. The Born-Qppenheimer approximation, viewed as "an unclean separation of variables" in the 10 to 100 dimensional (electrons + nuclei) versions of Schroedinger's partial differential equation of greatest interest to physical chemists.
9. The Born-Oppenheimer approximation applied to the vibrational normal modes (= SAVs = fast motions) of methanol as a function of the internal rotation angle (= LAM = slow motion).
10. The accumulation of geometric or Berry's phase in various SAV quantities in methanol after one complete internal rotation motion (after traversing one closed circuit in the LAM).
11. Jahn-Teller-like terms and Renner-Teller-like terms in the vibration-torsion Hamiltonian for the three CH stretching vibrations in methanol.
12. Inverted internal rotation splittings for 2 of the 3 CH stretching modes in methanol.
- Lecture 2, discussion of difficult ideas 75 min.
My first choice here is to have the students enrolled in the class ask questions related either to understanding Lecture 1 itself, or to understanding details found in papers published on the topics of Lecture 1 that have been bothering them. We would then try to answer the questions, or, for more difficult questions, discuss how to try to understand what the literature is saying. Two examples of places in the published literature where questions might arise are: (i) Sentences in a text book that do not give enough information to turn the words into quantum mechanical equations, and thus to understand in depth what is really being said. (ii) Statements or equations in literature articles that go beyond the student's (or beyond my) mathematical comfort level.
In case too few OSU students enrolled in the course have questions on any of the topics in Lecture 1, I will run out the clock with a mathematically action-packed 75-minute filler lecture, where I just give Lecture 1 over again, but this time with as many equations as possible.
- Lecture 3
Part 1, mostly words and pictures, about 30 minutes.
What is implied by the words "adiabatic and diabatic," when applied to quantum mechanical calculations on problems using the Born-Oppenheimer approximation?
An introduction using the diatomic vibronic literature, followed by slight reformulation of the ideas so they can be applied to vibrations in internally rotating methanol.
1. Adiabatic versus diabatic potential energy curves in diatomic molecules.
2. Adiabatic versus diabatic electronic and vibrational basis functions in diatomic molecules.
3. Adiabatic versus diabatic vibrational frequencies in methanol.
4. Adiabatic versus diabatic normal mode displacement vectors in methanol.
Part 2, some words, but mostly equations, about 45 minutes.
What are the advantages and disadvantages of carrying out "adiabatic" versus "diabatic" calculations in problems using the Born-Oppenheimer approximation?
This question is not yet answered for methanol = ongoing research problem.
5. Review of Jahn-Teller-like terms and Renner-Teller-like terms in the vibration-torsion Hamiltonian for the three CH stretches in methanol.
6. Why might one say that diabatic means the slow-fast interaction terms are in V of H = T + V, whereas adiabatic means the slow-fast interaction terms are in T of H = T + V?
7. Agreement between adiabatic versus diabatic torsion-vibration energy calculations for two simple algebraic models of torsion-vibration interaction in methanol.
8. Why might one say that quantum chemistry calculations "force us" to think (and calculate) adiabatically?
9. Adiabatic versus diabatic torsion-vibration energy calculations using Gaussian vibrational-frequency and normal-mode output for methanol.
February 25 - 5:30pm-6:30pm in 2136 Newman-Wolfrom - Pre-Lecture discussion by Dongping Zhong
Readings can be accessed on Carmen
February 27-28 Jun Ye, University of Colorado/JILA
Thursday February 27 - 9:35-10:55am in 2015MP - Lecture 1 - "Ultracold molecules - New frontiers in quantum and chemical physics"
Molecules cooled to ultralow temperatures provide fundamental new insights to molecular interaction dynamics in the quantum regime. In recent years, researchers from various scientific disciplines such as atomic, optical, and condensed matter physics, physical chemistry, and quantum science have started working together to explore many emergent topics related to cold molecules, including cold chemistry, strongly correlated quantum systems, novel quantum phases, and precision measurement.
Complete control of molecular interactions by producing a molecular gas at very low entropy and near absolute zero has long been hindered by their complex energy level structure. Recently, a range of technical tools have been developed enabling the production of ultracold molecules, including a quantum gas of molecules. In this regime, molecular collisions follow full quantum descriptions. Chemical reaction is controlled via quantum statistics of the molecules, along with long-range and anisotropic dipolar interactions. Further, molecules can be confined in reduced spatial dimensions and their interactions are precisely manipulated via external electric fields. Those efforts have started to yield observations on strongly interacting and collective quantum effects in an ultracold gas of molecules.
I will discuss some of the recent developments in science and technology in this field.
Readings: The emphasis of the Physics Today paper is on ultracold molecules, while the most recent review is on cold molecules.
Thursday February 27 - 5:30-7:00pm in 2136NW - Lecture 2 - student only
I will spend some time to go over any question students may have on the first lecture, discuss more specifically on technological side of things. I would also like to introduce optical frequency combs and their application for spectroscopy
"Optical frequency combs - from infrared to extreme ultraviolet"
Improvement of spectroscopy resolution has been a constant drive behind many scientific and technological breakthroughs over the past century, including the invention of laser and the experimental realization of ultracold atoms. State-of-the-art lasers can now maintain phase coherence beyond one second, that is, 1015 optical waves can pass by without losing track of a particular optical cycle. The recent development of optical frequency combs has allowed this unprecedented optical phase coherence to be established across the entire visible and infrared parts of the electromagnetic spectrum, leading to direct visualization and measurement of light ripples. A new generation of light-based atomic clocks has been developed, with measurement precision reaching below eighteen zeros after the decimal point, limited only by fundamental quantum mechanics. A novel application of frequency comb technology that leverages both the ultrashort duration of each pulse and the exquisite phase coherence of a train of pulses is the generation of frequency combs in the extreme ultraviolet (XUV), which we now use to directly uncover high resolution atomic spectra from 50 -100 nm.
Readings: Two references, one is a review published in 2010 (Annual Review Analytical Chemistry), the other is an earlier review paper on frequency combs (Rev Mod Phys, 2003).
- Friday February 28 - 9:35-10:55am in 2015MP - Lecture 3 The third lecture will include a very recent exciting development - the demonstration of the best atomic clock ever built. This is really intended to tell the students about the ultimate resolution and precision we are achieving in modern spectroscopy.
"Making the world's best clock"
The relentless pursuit of spectroscopy resolution has been a key drive for many scientific and technological breakthroughs over the past century, including the invention of laser and the creation of ultracold matter. State-of-the-art lasers now maintain optical phase coherence over many seconds and provide this piercing resolution across the entire visible spectrum. The new capability in control of light has enabled us to create and probe novel quantum matters via manipulation of dilute atomic and molecular gases at ultralow temperatures. For the first time, we control the quantum states of more than 1000 atoms so precisely that we achieve a more accurate and more precise atomic clock than any existing atomic clocks. With the clock accuracy and stability both reaching the 10-18 level, we now realize a single atomic clock with the best performance in both key ingredients necessary for a primary standard. We are also on the verge of integrating novel many-body quantum states into the frontiers of precision metrology, aiming to advance measurement beyond the standard quantum limit. Such advanced clocks will allow us to test the fundamental laws of nature and find applications among a wide range of technological frontiers.
Reading: 2008 review published in Science.
March 25 - 5:30pm-6:30pm in 2136 Newman-Wolfrom - Pre-Lecture discussion by Terry A. Miller
Readings can be accessed on Carmen
March 26-28 Gary Douberly, University of Georgia
- Lecture 1: Helium nanodroplet isolation (HENDI): The marriage of matrix isolation and molecular beams to form the "ultimate spectroscopic matrix".
Born from the marriage of cryogenic matrix isolation and molecular beam technologies, helium nanodroplet isolation (HENDI) has evolved into a versatile technique for molecular spectroscopy. Helium nanodroplets provide a medium for studying at 0.4 Kelvin, the structure and dynamics of novel systems such as biomolecules, free-radicals, metal clusters, and molecular clusters. In this lecture, a historical account will be presented that emphasizes several important hallmarks of the method, such as nanoscale superfluidity, nearly free molecular rotation of helium-solvated molecules, and the formation and kinetic trapping of metastable molecular assemblies.
J. P. Toennies, A. F. Vilesov, and K. B. Whaley, Superfluid helium droplets: An ultracold nanolaboratory, Phys. Today, 54, 2, 31 (2001).
K. K. Lehmann, and G. Scoles, The ultimate spectroscopic matrix?, Science, 279, 2065-2066 (1998).
G. Scoles and K. K. Lehmann, Nanomatrices are cool, Science, 287, 2429-2430 (2000).
- Lecture 2: (Students only) Helium nanodroplet isolation methodology and spectroscopic techniques.
This lecture will describe the details associated with helium droplet beam production, helium droplet doping, helium droplet detection, and the available laser based methods for spectroscopic studies of solvated molecules. Ongoing helium droplet experiments and possibilities for future breakthroughs will be discussed.
S. Yang and A. M. Ellis, Helium droplets: a chemistry perspective, Chem. Soc. Rev., 42, 458-471 (2013).
C. Callegari, K. K. Lehmann, R. Schmied, and G. Scoles, Helium nanodroplet isolation rovibrational spectroscopy: Methods and recent results, J. Chem. Phys., 115, 10090-10110 (2001).
G. E. Douberly, "Infrared Laser Spectroscopy of Dopants In and On Helium Nanodroplets: Rotational and Vibrational Dynamics (Chapter 2, HENDI Spectroscopy: Experimental Design and Concepts)", Ph.D. thesis, University of North Carolina, (2006).
- Lecture 3: Molecular radical reactions and carbene chemistry at 0.4 Kelvin: High-resolution rovibrational spectroscopy of pre-reactive complexes and transient intermediates along reaction paths.
The decade old technique of using superfluid helium droplets for the spectroscopic study of novel molecular species has only just started to move out of the world of chemical physics and into the realm of physical chemistry. Although the spectroscopy of molecules trapped in helium droplets have provided fascinating insights into the physical properties of the droplets, the actual observation of chemistry inside a 0.4 K helium droplet is only just beginning. Here we present some of the most recent advances in using helium droplets to address several important problems in atmospheric and combustion chemistry.
P. L. Raston, T. Liang, and G. E. Douberly, Infrared spectroscopy of HOOO and DOOO in 4He nanodroplets, J. Chem. Phys., 137, 184302 (2012).
C. M. Leavitt, C. P. Moradi, B. W. Acrey, and G. E. Douberly, Infrared laser spectroscopy of the helium-solvated allyl and allyl peroxy radicals, J. Chem. Phys., 139, 234301 (2013).
April 1 - 5:30pm-6:30pm in 2136 Newman-Wolfrom - Pre-Lecture discussion by Manfred Winnewisser
Readings (access pdfs on Carmen)
April 2-4 John Pearson Jet Propulsion Lab
- Lecture 1: April 2
A brief introduction to microwave-THz measurements. Then the lecture will focus on laboratory and in situ measurements.
Topics will include detection, molecular absorption, types of spectrometers, and practical aspects of building and optimizing such a system.
- April 3 - Frontiers students
- Lecture 2: April 4
Focus on microwave and THz remote sensing.
I will mostly focus on Passive sensing (Atmospheric and Astronomical) however I will discuss active sensing (Radar) as well. In this lecture I will spend more time discussing technology and future needs and opportunities
Grading: Satisfactory/Unsatisfactory options:
Class attendance and participation
Letter grade option: Class attendance and participation plus term paper
(Grades will be assigned solely by OSU faculty.)
(3 hours) Call number 29623 for ChemPhys 8880.01 (S/U option)
(3 hours) Call number 29624 for ChemPhys 8880.02 (graded option)
Physics 894 - 1998
Chemical Physics 894 - 1999
Chemical Physics 894 - 2000
Physics 880G20 - 2001
Physics 880G20 - 2002
Chemical Physics 894 - 2003
Chemical Physics 880 - 2004
Chemical Physics 880 -
Chemical Physics 880 -
2006 Chemical Physics 880 -
2007 Chemical Physics 880 -
2008 Chemical Physics 880 -
2010 Chemical Physics 880 -