The Neumark Group


Department of Chemistry, University of California Berkeley
and Chemical Science Division, Lawrence Berkeley National Laboratory

Slow photoelectron velocity-map imaging spectroscopy

Fast beam translational spectroscopy

Femtosecond Time-resolved photoelectron imaging

Molecular beam photodissociation dynamics

Spectroscopy and dynamics in helium droplets

Attosecond spectroscopy

Spectroscopy and dynamics in liquid microjets

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Molecular Beam Photodissociation Dynamics


We are currently modifying a crossed-molecular beam machine to experimentally probe the scattering dynamics of molecular beams from the surface of flat, microscopically thin jets of volatile liquids. The scattered species are mass selected and probed as a function kinetic energy and deflection angle from their original trajectory using time-of-flight mass spectrometry with a rotatable detector. Our capabilities of rotating both the liquid flat jet source and detector allow us to sample a large range of deflection angles. A tuneable electron impact ionizer enables isomer-specific identification of the scattered species by measurement of ionization efficiency curves.

We will start by studying the evaporation and scattering of noble and diatomic gases from the interfacial layers of volatile liquids such as dodecane and water. In the future we aim to characterize the dynamics of reactive scattering events at the surfaces of these liquids. We are especially interested in reactions relevant to atmospheric and industrial processes or those showcasing interesting manifestations of fundamental chemical physics.

Molecules studied:

Methylsulfinyl radical

Cyclopentadienyl radical

Fulvenallenyl radical


Methyl perthiyl radical

Project members:

Chin Lee

Marvin Pohl

Walt Yang

Schematic of the redesigned scattering machine

Microfluidic chip for flat jet production and liquid water flat jet

Recent publications:

♦ "Evaporation and molecular beam scattering from a flat liquid jet" C. Lee, M. N. Pohl, I. A. Ramphal, W. Yang, B. Winter, B. Abel, D. M. Neumark pdf

♦ "Photoelectron circular dichroism in angle-resolved photoemission from liquid fenchone" M. Pohl, S. Malerz, F. Trinter, C. Lee, C. Kolbeck, I. Wilkinson, S. Thurmer, D. M. Neumark, L. Nahon, I. Powis, G. Meijer, B. Winter, U. Hergenhahn P. C. C. P. 24, 8081 (2022). pdf

♦ "Photodissociation Dynamics of the Cyclohexyl Radical from the 3p Rydberg State at 248 nm" I. A. Ramphal, M. Shapero, D. M. Neumark J. Phys. Chem. A, (2021). pdf

♦ "Photodissociation dynamics of the methylsulfinyl radical at 248 nm" I. Ramphal, C. Lee, D. M. Neumark, Mol. Phys. 117, 3043 (2019). pdf