About

Valeria D. Kleiman is a Professor in the Department of Chemistry at the University of Florida. Her research focuses on using time-resolved ultrafast spectroscopy to investigate the excited state properties of synthetic materials. She seeks to understand interactions among chromophores, the role of wave packet localization and delocalization in enhancing or suppressing energy and electron transfer, and the interplay between coherent and incoherent processes to modulate the efficiency of energy transfer. Her work aims to build fundamental knowledge on light-matter interactions in light-harvesting materials. In addition to her research in physical chemistry, Kleiman is involved in chemical education projects. She investigates how to effectively incorporate chemistry education for different student populations, exploring factors that impact disparities in outcomes for transfer students and assessing the effectiveness of new pedagogical tools in the classroom. Her educational background includes a Ph.D. in Chemistry from the University of Illinois at Chicago and a postdoctoral fellowship at the National Institute of Standards and Technology. She has received several awards, including the UF-CLAS International Educator Award and the CLAS College Teacher of the Year, and has served as a visiting professor at the University of Buenos Aires.

Research topics

• Photochemistry
• Chemistry
• Organic chemistry
• Physics
• Optoelectronics
• Atomic physics
• Chemical physics
• Materials science
• Nanotechnology
• Environmental chemistry

Selected publications

• Immersive stereochemistry: Using virtual reality (VR) to understand chirality with undergraduate students

  2020-05-01

  preprintSenior author
  PublisherDOI

• Immersive stereochemistry: Using virtual reality (VR) to understand chirality with undergraduate students

  2020-05-01

  preprintSenior author
  PublisherDOI

• Photochemistry of Ru precursors for photoassisted chemical vapor deposition

  2020-04-28

  preprintOpen access

  Quantum yields for loss of a single CO ligand in alkane solutions were determined for the (η³-allyl)Ru(CO)₃X complexes, where X = Cl, Br, I, and various (diene)Ru(CO)₃ complexes. Excited states were assigned as MLCT or LF on the basis of solvatochromism and DFT studies. The solution phase photochemistry was proposed to occur by excitation of an MLCT

  PublisherDOI

• Unraveling Direct and Indirect Energy Transfer Pathways in a Light-Harvesting Dendrimer

  The Journal of Physical Chemistry C · 2020 · 25 citations

  • Chemical physics
  • Materials science
  • Nanotechnology

  Light-harvesting and intramolecular energy funneling are fundamental processes in natural photosynthesis. A comprehensive knowledge of the main structural, dynamic, and optical properties that regulate the efficiency of such processes can be deciphered through the study of artificial light-harvesting antennas, capable of mimicking natural systems. Dendrimers are some of the most explored artificial light-harvesting molecules. However, they have to be well-defined and highly branched conjugated structures, creating intramolecular energy gradients that guarantee efficient and unidirectional energy transfer. Herein, we explore the contributions of the different mechanisms responsible for the highly efficient energy funneling in a large, complex poly(phenylene–ethynylene) dendrimer, whose architecture was particularly designed to conduct the initially absorbed photons toward a spatially localized energy sink away from its surface, avoiding its quenching by the environment. For this purpose, the nonradiative photoinduced energy relaxation and redistribution are simulated by using nonadiabatic excited state molecular dynamics. In this way, the two possible direct and indirect pathways for exciton migrations, previously reported by time-resolved spectroscopy, are defined. Our results stimulate future developments of new synthetic dendrimers for applications in molecular-based photonic devices in which an enhancement in the photoemission efficiency can be predicted by changes in the detailed balance between the different intramolecular energy transfer pathways.

  PublisherOA PDFDOI

• Photochemistry of Ru precursors for photoassisted chemical vapor deposition

  2020

  • Photochemistry
  • Chemistry
  • Organic chemistry
  PublisherDOI

• Photochemistry of Ru precursors for photoassisted chemical vapor deposition

  2020

  • Photochemistry
  • Chemistry
  • Environmental chemistry
  PublisherDOI

• Photochemistry of (η³-allyl)Ru(CO)₃X Precursors for Photoassisted Chemical Vapor Deposition

  Organometallics · 2019-10-14 · 10 citations

  article

  Quantum yields for loss of a single CO ligand in alkane solutions were determined for the (η3-allyl)Ru(CO)3X complexes, where X = Cl, Br, I. The three complexes had similar quantum yields at λexc = 254 nm, while the quantum yields obtained at 313 nm followed a trend of ΦBr > ΦCl > ΦI. A wavelength dependence of the quantum yields in the order Φ254 < Φ313 < Φ334 was observed for the iodo complex. Very low levels of luminescence were observed for the compounds, demonstrating that radiative decay of the excited states was not competitive with nonradiative processes, including photochemical reactions. Excited states were assigned as MLCT or LF on the basis of solvatochromism and DFT studies.

  PublisherDOI

• Implementing New Educational Platforms in the Classroom: An Interactive Approach to the Particle in a Box Problem

  Journal of Chemical Education · 2019-07-11 · 17 citations

  articleSenior authorCorresponding

  The ready availability of interactive platforms has produced a new generation of students able to utilize computer-based learning tools with ease and comfort. The potential to better “explore by yourself” the lecture material permits students to have an enhanced learning experience and stimulates them to tinker with equation parameters generating insightful figures or animations. Used in the classroom, it emboldens students to have a deeper comprehension of complex derivations or mathematical expressions. We illustrate the power of interactive learning platforms by presenting educational Jupyter notebooks for the study of a fundamental problem in quantum chemistry: the motion of a particle in 1D and 2D space. Although simple, this model offers the possibility to explore several important quantum chemistry concepts such as Heisenberg’s uncertainty principle, confinement leading to quantization, tunneling effect, and even bonding and antibonding properties. We present four Jupyter notebooks that gradually walk the student from the properties of a free particle to the properties of a particle in a double potential well. Our experience gained from the implementation of the material in the undergraduate and graduate curriculum is discussed, including student feedback and examples of complementary homework to be used in the classroom.

  PublisherDOI

• Coherent exciton-vibrational dynamics and energy transfer in conjugated organics

  Nature Communications · 2018-06-07 · 91 citations

  articleOpen access

  Coherence, signifying concurrent electron-vibrational dynamics in complex natural and man-made systems, is currently a subject of intense study. Understanding this phenomenon is important when designing carrier transport in optoelectronic materials. Here, excited state dynamics simulations reveal a ubiquitous pattern in the evolution of photoexcitations for a broad range of molecular systems. Symmetries of the wavefunctions define a specific form of the non-adiabatic coupling that drives quantum transitions between excited states, leading to a collective asymmetric vibrational excitation coupled to the electronic system. This promotes periodic oscillatory evolution of the wavefunctions, preserving specific phase and amplitude relations across the ensemble of trajectories. The simple model proposed here explains the appearance of coherent exciton-vibrational dynamics due to non-adiabatic transitions, which is universal across multiple molecular systems. The observed relationships between electronic wavefunctions and the resulting functionalities allows us to understand, and potentially manipulate, excited state dynamics and energy transfer in molecular materials.

  PublisherOA PDFDOI

• Coherent exciton-vibrational dynamics and energy transfer in conjugated organics

  Americanae (AECID Library) · 2018-06-13

  articleOpen access

  Coherence, signifying concurrent electron-vibrational dynamics in complex natural and man-made systems, is currently a subject of intense study. Understanding this phenomenon is important when designing carrier transport in optoelectronic materials. Here, excited state dynamics simulations reveal a ubiquitous pattern in the evolution of photoexcitations for a broad range of molecular systems. Symmetries of the wavefunctions define a specific form of the non-adiabatic coupling that drives quantum transitions between excited states, leading to a collective asymmetric vibrational excitation coupled to the electronic system. This promotes periodic oscillatory evolution of the wavefunctions, preserving specific phase and amplitude relations across the ensemble of trajectories. The simple model proposed here explains the appearance of coherent exciton-vibrational dynamics due to non-adiabatic transitions, which is universal across multiple molecular systems. The observed relationships between electronic wavefunctions and the resulting functionalities allows us to understand, and potentially manipulate, excited state dynamics and energy transfer in molecular materials.

  PublisherDOI

Recent grants

• CAREER: Ultrafast studies of exciton transport in conjugated polymers

  NSF · $548k · 2003–2009

• Understanding Energy and Electron Transfer in Multi-Metal Coordination Compounds

  NSF · $562k · 2018–2023

• Coherent and Incoherent Energy Transfer in Conjugated Molecules

  NSF · $450k · 2011–2016

Frequent coauthors

• Adrián E. Roitberg

  University of Florida

  39 shared

• Sergei Tretiak

  Los Alamos National Laboratory

  37 shared

• Sebastian Fernández-Alberti

  Consejo Nacional de Investigaciones Científicas y Técnicas

  36 shared

• Edwin J. Heilweil

  Physical Measurement Laboratory

  33 shared

• Joseph S. Melinger

  United States Naval Research Laboratory

  28 shared

• Alejandro Cadranel

  Fundación Ciencias Exactas y Naturales

  21 shared

• Luis M. Baraldo

  Fundación Ciencias Exactas y Naturales

  19 shared

• Todd A. Heimer

  16 shared

Awards & honors

• Visiting Professor of Physics, University of Buenos Aires, A…
• UF-CLAS International Educator Award (2018)
• CLAS College Teacher of the Year (2015)
• AGAUR, Scholar Award, Catalunya, Spain (2011)
• NSF CAREER (2003)