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Full-Text Articles in Physical Sciences and Mathematics
Heterogeneity Of Reaction Rates In An Ionic Liquid: Quantitative Results From 2d- Muppets, Kalyanasis Sahu, Sean Kern, Mark Berg
Heterogeneity Of Reaction Rates In An Ionic Liquid: Quantitative Results From 2d- Muppets, Kalyanasis Sahu, Sean Kern, Mark Berg
Sean J. Kern
The hypotheses that ionic liquids are structurally heterogeneous at the molecular level and, even further, that this heterogeneity can transfer to the rates of reactions run in ionic liquids is being actively debated. Here, this hypothesis is tested using multiple population-period transient spectroscopy (MUPPETS), an emerging type of multidimensional measurement that resolves the kinetics of subensembles within a heterogeneous sample. A previous MUPPETS study of the excited-state twisting and electronic relaxation of auramine indicated that an ionic-liquid solvent induces rate dispersion due to a combination of heterogeneous and homogeneous processes, but those data could not quantitatively separate these contributions [Khurmi, …
Separating Sub-Ensembles On Ultrafast Timescales: Multiple Population-Period Transient Spectroscopy (Muppets), Kalyanasis Sahu, Sean Kern, Mark Berg
Separating Sub-Ensembles On Ultrafast Timescales: Multiple Population-Period Transient Spectroscopy (Muppets), Kalyanasis Sahu, Sean Kern, Mark Berg
Sean J. Kern
No abstract provided.
Well-Resolved Coherent Raman Spectra From Femtosecond Pulses, Sukhendu Nath, Diana Urbanek, Sean Kern, Mark Berg
Well-Resolved Coherent Raman Spectra From Femtosecond Pulses, Sukhendu Nath, Diana Urbanek, Sean Kern, Mark Berg
Sean J. Kern
This paper demonstrates a method for measuring coherent anti-Stokes Raman spectra with a resolution limited only by the inherent linewidth of the sample, even when using pulses of a width (60 fs, 300 cm−1) that is between the widths needed for a pure frequency- or time-domain measurement. Data are collected as a function of both delay and frequency and used to recover a standard Raman spectrum. The resulting time/frequency detected experiment represents a bridge between standard time- and frequency-domain approaches to spectroscopy.
Simultaneous Time And Frequency Detection In Femtosecond Coherent Raman Spectroscopy, Sukhendu Nath, Diana Urbanek, Sean Kern, Mark Berg
Simultaneous Time And Frequency Detection In Femtosecond Coherent Raman Spectroscopy, Sukhendu Nath, Diana Urbanek, Sean Kern, Mark Berg
Sean J. Kern
The preceding paper showed that, in principle, a high-resolution coherent Raman spectrum can be recovered using femtosecond probe pulses by combined detection in both time and frequency. This measurement is possible even when the pulses are too broad in frequency for conventional frequency-domain spectroscopy and too broad in time for conventional time-domain spectroscopy. In this paper, the method is tested on experimental coherent anti-stokes Raman spectroscopy data from acetonitrile. Compared to theoretical models, experimental data are complicated by noise and incomplete knowledge of the pulse structure. Despite these complications, most of the information in the Raman spectrum is recovered from …
High-Resolution Raman Spectra With Femtosecond Pulses: An Example Of Combined Time- And Frequency-Domain Spectroscopy, Sukhendu Nath, Diana Urbanek, Sean Kern, Mark Berg
High-Resolution Raman Spectra With Femtosecond Pulses: An Example Of Combined Time- And Frequency-Domain Spectroscopy, Sukhendu Nath, Diana Urbanek, Sean Kern, Mark Berg
Sean J. Kern
Frequency-domain spectroscopy requires long pulses, whereas time-domain spectroscopy requires short pulses. This Letter demonstrates both theoretically and experimentally that simultaneous detection in frequency and time generates well-resolved spectra using intermediate-length pulses. In the case of coherent Raman spectroscopy, typical femtosecond pulses lie between the time and frequency domains. To demonstrate this method, a high-resolution Raman spectrum of nitrobenzene is obtained from 60 fs pulses. Phase control, pulse shaping, or pulses of widely differing duration are not required.