Using OM PPS methods we can highly selectively identify many key details of electron-spin structures and processes in all molecular systems and in various different spectral regions from X-ray to IR and beyond. Key decision making steps in these processes are characterized by ultrafast (femto and sub-femto) time scales and therefore require highly selective spatially-temporally and objects resolved methods – such as those that we now develop in the unique environment of cells 1-3-5 at the NHMF laboratory. With well-defined precise PPS Spatio-Temporal Electro-Magnetic Processes/structures (STEMP) based on 25T field and < 15 fs laser pulses we can identify signatures of molecular processes better than 10-9 in comparison to similar non-PPS methods. Using <20fs and 25T Split-helix magnet at NHMF lab we have developed and tested OM PPS configurations (July 2014, cell 5) that can monitor previously unseen electron-spin couplings and correlations, even in soft matter systems of our interest. Earlier, we have successfully used <100fs sub-K (3He) - high magnetic flux (~10 T, cell 1) PPS instrumentation setup at the NHMF Laboratory. Indeed, OM PPS studies can significantly improve our understanding of electronic processes and structures even in the most complex processes of paramount interest in medicine:  our recent discoveries at LSU and NHMF opened a completely new insight into the various different forms of Fe-S clusters in some key enzymes.  Clear PPS signatures of electron (de)localization in active units are for the first time detected. Such active centers are known to be involved in the reduction-oxidation, ET, catalysis, biosynthesis and photosynthesis, as well as controlled synthesis. NHMFL and LSU work at higher magnetic fields resulted in new findings about the fundamental electron spin related properties which challenge earlier model predictions. For example, our recent studies of the magnetic PPS VT-MCD signatures of the key steps in the reduction processes of some nitrogenase related Fe-S clusters and the ongoing TO studies have been accepted in the scientific community with great interest. They not only challenge previous predictions and interpretations, but also provide a solid base for novel STEMP-based electron interaction models development.



Name:        Dr  Kresimir Rupnik, Ph.D.                                                         Citizen: USA

Office:     Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803

Phone:         (225) 205-1353 (work cell phone, 24/7)    (225) 578-2945 (Chemistry, LSU)

E-mail/web: or

Field of specialization: Chemical/Molecular Physics-photonics, Physical- Analytical- Chemistry

 Previous results and ongoing work



(A) Reversible redox titration of ΔnifB NifEN, where a Nernst curve is represented by the solid line. Blue and red points represent samples used to collect the MCD spectra in panel B. (B) MCD spectra of ΔnifB NifEN


HMF-PPS measurements can improve our understanding of electronic processes in enzymes even in the most complex environments of paramount interest to biophysics and medicine, Our OMPPS high field measurements

and  findings about FeS based electronic processes challenge earlier model predictions (Rupnik at all JACS, 2011-12,  Biophysics 2014). Of interest is ongoing 12fs PPS OM study that could provide inside in selective correlated electronic events.

. (A) MCD spectra of IDS-oxidized ΔnifB NifEN (red) and ΔnifH MoFe protein (green, scaled by a factor of 0.5). (B) First derivative MCD spectra of oxidized ΔnifB NifEN (red) and ΔnifH MoFe protein (green, scaled by a factor of 0.5), showing nearly identical transitions in both cases. (C) MCD spectra of reduced ΔnifB NifEN (red) and ΔnifH MoFe protein

MCD magnetization of L127DFe-MoFe Av 1 protein, at ~500mK @ 410nm, a multi-component spin system  At NHMF lab, we canobtained much higher selectivity which resulted in new information about enzymatic structures and synthesis patterns.


MCD magnetization of Av1 DnihB MoFe: blue, at  1.63K @ 520nm (LSU), red at 1.577K @410nm  (NHMF, this work covers 10T). Pulses~100fs, 70MHz 

FSHM measurements- magnetizations of porphyrin FeCl(TPP)  shown from  -24.5 to 24.5 T

Typical UF OM  PPS- differential PPS magnetization curve - ~15fs  , 800nm centered pulse directed into electronic transitions area.  MCD curve  is shown below. Events are driven in broadband region, 80  MHz


FSHM measurements- MCD of porphyrin FeCl(TPP)  shown from  -24.5 to 24.5 T measurements. A larger set of porphyrins is investigated for new unexpected electronic structures


OM PPS spectra of a Fe4S4- protein. Temperature with sapphire windows ~10K. A shift of the peak at 520->580nm is observed at VT. Results are different from low field: different view of correlated coupled electrons

Typical UF OM PPS- differential PPS structure - ~15fs  , 800nm centered pulse directed into electronic transitions area.  Magnetization curve  is shown above from 0 to 25T. Events are driven in broadband region

High OM PPS can significantly modulate temporal phase and also help  selectively resolve diferent spatio-temporal contributions. We investigate now presence of oscillatory structures below 100fs. Here some models predict new important couplings


OUR OM HF UF PPS ~ 15fs measurements  in various different spectral regions is based on several new PPS technological solutions

Sample preparation and presentation

technology presents one of the most

significant challenges and one of the great successes of the previous OM PPS  work at NHMFL.

At sub 15fs , STEMPS measurements and characterizations require new instrumental configurations for photonic auto- and cross-correlations

Femtosecond scale signal from a PPS.PPS method provide multidimensional data: spatial, temporal frequency, and phase information-higher selectivity and better STEMP resolution.  Polarization selection is achieved with two polarizers.



1986-present   Faculty-Research Scientist,  Department of Chemistry, Louisiana State University, Baton Rouge, LA

1984-85      Postdoctoral Researcher in Physical Chemistry, Department of

                    Chemistry, University of North Carolina, Chapel Hill, NC  (NSF)

Awarded Projects/Grants: Research in the last 20 years included projects supported by NSF, USDoA, NIH, DOD, DOE and other funding agencies.

-NSF(Collaborative Investigator) – (September2012-5 years) : “Development of Ultrafast Spectroscopy System for Chemistry , Materials Science and Biophysics Research and Education in the 25-T Split-Coil Helix”

- (PI) NHMF -## (new 2014-2016), “Ultrafast  STEMP Polarization Phase Selective Studies”-

- (PI) NHMF -## (20012-2014), “Ultrafast Polarization Phase Selective Studies”-

- (PI) NHMF -## (2007-2012), “Polarization Phase Selective Studies”-

-Collaborative projects Dr. Brian Hales LSU (2000-2014) and Dr Markus Ribbe  UC Irvine, (NIH  GM67626  and NSF funds, BoR, EPSCOR funds) ,

-(DOE, NIH) Collaborative projects at Argonne National Laboratory, Advanced Photon Source, 2002-present.

- DOE (Co-PI), "A Physico-Chemical Study of Some Areas of Fundamental Significance  to Biophysics" (project from 1986)

-LEQSF (PI), “Radiation Signatures” (1996)

-Collaboration on science education projects: NSF “Scientific Visualization” 2007-present, NSF “Student retention project”, 2007-present.


 Selected Publications:

1.  K Rupnik, C. Lee, J. A. Wiig, Y. Hu, M. W. Ribbe, and B. J. Hales , “Non-Enzymatic Synthesis of the P-Cluster in the Nitrogenase MoFe Protein: Evidence for the Involvement of All Ferrous Intermediates”, Biochemistry, 55 ( 2014) 1108

2. J. Dumke, A. Qureshi, S. Hadman, S. Das, K. Rupnik, B El-Zahab, D. J. Hayes, I. M. Warner, “Tumor-Targeting Hyperthermal near Infrared Nano GUMBOS”, Photochem. Photobiol. Sci. (submitted 2014).

3. K. Rupnik PI, “NHMFL PPS Studies Project Report 2010- 2013“, NHMFL, 2013

4. K. Rupnik, Y. Hu, C. C. Lee, J. A. Wiig, M. W. Ribbe and B.J. Hales, “P+ State of Nitrogenase P-Cluster exhibits Electronic Structure of a [Fe4S4]+ Cluster”, J. Am. Chem. Soc. 134 ( 2012) 13749

5. K. Rupnik, C. C. Lee, Y. Hu, M. W. Ribbe, B. J. Hales, “[4Fe4S]2+ Clusters Exhibit Ground-State Paramagnetism”, J. Am. Chem. Soc. 133 (2011) 6871.

6. K. Rupnik, Yilin Hu, Aaron W. Fray, Markus Ribbe, and Brian J. Hales, “VTVH-MCD Spectroscopic Study of  NifEN-Bound precursor”, J. Biol. Inorg. Chem., 16  (2011) 325.

7. T.  Brown, Z. LeJeune, K. Liu, S. Hardin, J-R Li, K. Rupnik, and J. C. Garno, “Automated scanning probe lithography with n-alkanethiol self assembled monolayers on Au(111): Application for teaching undergraduate laboratories” , JALA,16 (2) (2011) 112.

8. D. Shafir, Y. Mairesse, H. J. Worner, K. Rupnik, D.M. Villeneuve, P. B. Corkum and N. Dudovich, “Probing the symmetry of atomic wavefunction from the point of view of strong field driven electrons” , New Journal of Physics 12, 073032 (2010)

9. Marcia S. Cotton, Kresimir Rupnik, Robyn B. Broach, Yilin Hu, Aaron W. Fay, Markus W. Ribbe and Brian J. Hales VTVH-MCD Study of the DnifBDnifZ MoFe Protein from Azotobacter vinelandii, J.  Am. Chem.  Soc.,  131 (13) (2009) 4559.

10. K. Rupnik PI, “NHMFL PPS Studies Project Report 2008 and 2009“,NHMFL 2009

11. R. Broach, K. Rupnik, M. Ribbe, B, J, Hales, ”MCD Spectroscopic Investigations of the Different Oxidation States of the DnifH apo-MoFe protein from A. vinelandii”, Biochemistry 2006, 45  15039-15048.

12. Uwe Bergmann, Wolfgang Sturhahn, Donald E. Linn, Jr.,Francis E. Jenney, Jr., Michael W. W. Adams, Kresimir Rupnik, Brian J. Hales, Ercan E. Alp, Aaron Mayse, and Stephen P. Cramer, “Observation of Fe-H/D Modes by Nuclear Resonant Vibrational Spectroscopy“,J.  Am. Chem.  Soc. 125, 4016 (2003)

13. S. P. McGlynn, P. Brint, J. D. Scott, and K. Rupnik, in "Understanding Chemical Reactivity: The Role of Rydberg States in Spectroscopy and Photochemistry", edited by C. Sandorfy, (Kluwier Academic, Norwell, MA, 1999), p. 121.

14. A. Vrancic, K. Rupnik, L. Klasinc, and S. P. McGlynn, "Time-Resolved Profiles in Modulated Polarization Spectroscopy", J. Chem. Info. Comput. Sci.  39, 68 (1999).

15. A. Vrancic, K. Rupnik, and S. P. McGlynn, “A Selective Digital Integrator for Modulated-Polarization Spectroscopy: An Evaluation using (+)-3 Methylcyclopentanone,” Rev. Sci. Instrum. 69,40(1998).

16. K. Rupnik and S. P. McGlynn, "The Simulation of an Unusual Magnetic Circular Dichroism Spectrum: The 5pà 6s Transition of HI", J. Chem. Phys. 103, 7661 (1995).

17. K. Rupnik, U. Asaf, and S. P. McGlynn, in "Gaseous Dielectrics VII" , edited by L. C. Christophorou, (Plenum, New York, 1994), p. 87.

18. K. Rupnik, L. Klasinc, M. Varma, J. Battista, and S. P. McGlynn, "Lesion Spectra: Radiation Signatures and Biological Gateways", J. Chem. Info. Comput. Sci. 34, 1054 (1994).

19. U. Asaf, K. Rupnik, G. Reisfeld, and S. P. McGlynn, "Pressure Shifts and Electron Scattering Lengths in Atomic and Molecular Gases", J. Chem. Phys. 99, 2560 (1993).

20. M. Eckert-Maksic, Z. B. Maksic, M. Hodoscek, and K. Rupnik, "Inter and Extramolecular Electrostatic Potentials in Vitamin C", J. Mol. Struct. THEOCHEM, 256, 271 (1992).

21. W. S. Felps, K. Rupnik, and S. P. McGlynn, "Electronic Spectroscopy of Cyanogen Halides", J. Phys. Chem. 95, 639 (1991).

22. K. Rupnik, U. Asaf, and S. P. McGlynn, "Electron Scattering in Dense Atomic and Molecular gases: An Empirical Correlation of Polarizability and Electron Scattering Length", J. Chem. Phys. 92, 2303 (1990).

23. K. Rupnik, "VUV and Laser Raman Study of the Atomic and Molecular Polarizabilities", in Lasers98, edited by D. G. Harris, (STS Press, McLean, VA,1990), p. 774.

24. R. G. Parr, K. Rupnik and S. Gosh, "Phase-Space Approach to the Density Functional Calculation of Compton Profiles of Atoms and Molecules", Phys. Rev. Letts.  56, 1555 (1986).