Mass spectrometry of aerosol particle analogues in molecular beam experiments

Abstract

Nanometer-size particles such as ultrafine aerosol particles, ice nanoparticles, water nanodroplets, etc, play an important, however, not yet fully understood role in the atmospheric chemistry and physics. These species are often composed of water with admixture of other atmospherically relevant molecules. To mimic and investigate such particles in laboratory experiments, mixed water clusters with atmospherically relevant molecules can be generated in molecular beams and studied by various mass spectrometric methods. The present review demonstrates that such experiments can provide unprecedented details of reaction mechanisms, and detailed insight into the photon-, electron-, and ion-induced processes relevant to the atmospheric chemistry. After a brief outline of the molecular beam preparation, cluster properties, and ionization methods, we focus on the mixed clusters with various atmospheric molecules, such as hydrated sulfuric acid and nitric acid clusters, N O and halogen-containing molecules with water. A special attention is paid to their reactivity and solvent effects of water molecules on the observed processes.

Ring Formation and Hydration Effects in Electron Attachment to Misonidazole

“…We used a source of microhydrated clusters [27] and a reflectron time-of-flight mass spectrometer (RTOF) [28], which are parts of the complex CLUster Beam (CLUB) setup [29]. The beam of microhydrated MISO was prepared by co-expanding a mixture of a buffer He or Ne gas, humidified by the Pergo gas humidifier system, together with sublimed MISO (98% purity, Toronto Research Chemicals) through a 90 μm nozzle into vacuum (10−4 mbar range during the experiment).…”

Pickup and reactions of molecules on clusters relevant for atmospheric and interstellar processes

“…From the perspective of atmospheric chemistry, the cluster research can provide detailed insight into aerosol formation and reactions. 42,43 Despite huge experimental and theoretical efforts, aerosol particles still belong to the least known players in atmospheric chemistry. 42,[44][45][46][47] Nevertheless, their importance is unquestionable; among many other effects, they provide surfaces for heterogeneous chemistry and photochemistry.…”

Influence of H2O and NH3 on the reaction of HO2 with NO in troposphere: Theoretical investigation of HNO3 formation pathways

“…In Equation 2, H 2 O may have an obvious effect by increasing the stability of reactant complexes, reducing the activation energy of transition states, [25] and having obviously solvent effects on the chemical reaction. [26][27][28][29] Thus, Butkovskaya et al [7] studied the effects of water monomer on the HO 2 + NO ! HNO 3 reaction.…”

“…In Equation ), H 2 O may have an obvious effect by increasing the stability of reactant complexes, reducing the activation energy of transition states, [ 25 ] and having obviously solvent effects on the chemical reaction. [ 26–29 ] Thus, Butkovskaya et al [ 7 ] studied the effects of water monomer on the HO 2 + NO → HNO 3 reaction. In their work, the influence of water vapor on the production of HNO 3 in the gas‐phase HO 2 + NO reaction was determined at 298 K using a high‐pressure turbulent flow reactor coupled with a chemical ionization mass spectrometer.…”