2.3 Cluster Reaction Apparatus
25
Fig. 2.8 A sketch showing the showing the compact flow-tube reactor combined with a home-made
reflection time-of-flight mass spectrometer (Re-TOFMS) in Luo’s group
others, customized reaction cells have also been applied by a few other research
groups such as Bowen’s [157], allowing studies of photoelectron spectroscopy of the
in situ synthetic clusters.
2.4 Detection and Characterization
2.4.1 Cluster Mass Spectrometry
As the detection of a slow neutral cluster seems to be impossible, the clusters have
to be ionised for an efficient mass-selective detection. Simply by measuring the
ions abundance relating to mass-to-charge ratios, mass spectrometry is the unique
tool for identifying the quantity and type of clusters and their reaction products.
According to the mass analysis techniques, the most popular candidates for mass
spectrometry include quadrupole mass spectrometer (QMS), ion-trap mass spectrometer (ITMS), and time-of-flight mass spectrometer (TOFMS). Among others,
tandem quadrupole/ion-trap mass spectrometer and Fourier transform ion cyclotron
resonance (FT-ICR) mass spectrometer have also been used in cluster reaction investigations [180–182]. In tandem mass spectrometry, the cluster ions successively lose
energy due to the nonreactive collisions with background gasses and the adiabaticity
of the multipole [55, 56]. Temperature-controlled tandem mass spectrometers are
available but the technique is not as precise as the laminar flow tube and generally
can only be controlled when lower than room temperature [183]. FT-ICR mass spectrometry adds resonance excitation to the trapped species hence enabling analysis of
internal energy distributions [184–186].
25
Fig. 2.8 A sketch showing the showing the compact flow-tube reactor combined with a home-made
reflection time-of-flight mass spectrometer (Re-TOFMS) in Luo’s group
others, customized reaction cells have also been applied by a few other research
groups such as Bowen’s [157], allowing studies of photoelectron spectroscopy of the
in situ synthetic clusters.
2.4 Detection and Characterization
2.4.1 Cluster Mass Spectrometry
As the detection of a slow neutral cluster seems to be impossible, the clusters have
to be ionised for an efficient mass-selective detection. Simply by measuring the
ions abundance relating to mass-to-charge ratios, mass spectrometry is the unique
tool for identifying the quantity and type of clusters and their reaction products.
According to the mass analysis techniques, the most popular candidates for mass
spectrometry include quadrupole mass spectrometer (QMS), ion-trap mass spectrometer (ITMS), and time-of-flight mass spectrometer (TOFMS). Among others,
tandem quadrupole/ion-trap mass spectrometer and Fourier transform ion cyclotron
resonance (FT-ICR) mass spectrometer have also been used in cluster reaction investigations [180–182]. In tandem mass spectrometry, the cluster ions successively lose
energy due to the nonreactive collisions with background gasses and the adiabaticity
of the multipole [55, 56]. Temperature-controlled tandem mass spectrometers are
available but the technique is not as precise as the laminar flow tube and generally
can only be controlled when lower than room temperature [183]. FT-ICR mass spectrometry adds resonance excitation to the trapped species hence enabling analysis of
internal energy distributions [184–186].