Three-Dimensional Representation Of Typical Ambient Particles Using FIB-SEM
Diana L. Ortiz-Montalvo and Joseph M. Conny
Ambient particles are ubiquitous in the atmosphere and exert a strong influence on the climate by
altering the Earth’s radiative balance. The scattering and absorption properties of aerosols
depend highly on the diverse chemical composition, structures, sizes, and shapes of the particles.
Furthermore, hidden imbedded phases and voids are commonly present in heterogeneouslymixed particles and can affect the optical properties of particles as well as their projected effect
on climate.
This study combines advanced microscopy techniques and optical property modeling to
understand how morphology and composition of individual atmospheric particles affect their
optical properties. Ambient particles were analyzed using focused ion-beam scanning electron
microscopy (FIB-SEM) and energy-dispersive x-ray spectroscopy (EDX) to obtain images and
elemental composition of numerous slices for each particle. The FIB-SEM-EDX analysis has the
main advantage of imagining hidden imbedded phases and voids that are difficult to detect using
conventional SEM. The structural and compositional data obtained for each particle slice using
FIB-SEM-EDX was then used to reconstruct the three-dimensional (3D) configuration of the
particle. The light-absorbing and light-scattering inclusions and voids inherent in the particles
were mapped during the 3D reconstruction.
The use of FIB-SEM-EDX data to reconstruct the 3D composition of individual particles creates
an innovative and powerful venue to study aerosol optical properties using optical property
modeling (e.g., Discrete Dipole Approximation method). Lastly, we used the reconstructed 3D
models of these particles in 3D printers to obtain handheld models of these microscopic particles,
which we have already used in various outreach activities and demonstrations.
Name: Diana L. Ortiz-Montalvo
Sigma Xi member? No
Advisor’s Name: Joseph M. Conny
Division: 643
Laboratory: MML
Office (Bldg./Office): 217/A103
Mail Stop: 8372
Phone: x2019
E-mail: Diana.Ortiz-Montalvo@NIST.gov
Postdoc category: NRC
Poster Category:Chemistry