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

Liquid flat jet molecular beam scattering

Spectroscopy and dynamics in helium droplets

Attosecond spectroscopy

Spectroscopy and dynamics in liquid microjets

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Liquid Flat Jet Molecular Beam Scattering


A newly built molecular beam scattering apparatus that utilizes a flat liquid jet allows us to experimentally probe the scattering dynamics of molecular beams from the surface of flat, microscopically thin jets of volatile liquid, and in turn, the highly chemically relevant gas-liquid interface. The scattered species are analyzed by a rotatable mass-spectrometer which provides mass, energetic, and angular selectivity. The capacity to rotate both the flat liquid jet and detector enables us to sample a large range of incident and outgoing angles. A tunable electron impact ionizer enables isomer-specific identification of the scattered species by measurement of ionization efficiency curves.

We have studied the evaporation and scattering of neon from a dodecane flat liquid jet, extracting relevant information on scattering and energetic distributions at various deflection angles. The latter gives us the ability to examine energy loss of the incident beam through kinematic models. The dynamics of reactive scattering events are at the forefront of our interests, leading us to future work focusing on more volatile solutions. For example, studying water-based systems such as CO2 scattering from monoethanolamine (MEA) solution and SO3 scattering from salty water will provide more insight onto water-based catalysis and atmospheric chemistry.

Systems studied:


Dodecane–deuterium oxide



Project members:

Chin Lee

Steve Saric

Walt Yang

Schematic of the scattering machine

Microfluidic chip for flat jet production and representative liquid 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