The project resulted in development of the theory of rotationally-resolved two-dimensional infrared (RR2DIR) spectroscopy.
This theory lays the groundwork for further more detailed investigations of, for example, collisional effects in the spectra or of anharmonic couplings between different vibrational modes.
Two specific features of RR2DIR spectroscopy were investigated more deeply: polarization dependence and waiting time dependence of the molecular response.
The work on polarization dependence resulted in general classification of the molecular response into seven distinct classes.
This enabled derivation of special polarization sequences of incident pulses that turn off specific parts of the 2D spectrum and that greatly simplify the spectrum.
This result will be especially important for detection of complex gas mixtures, such as those found in human breath or in other complex chemical environments, since simplifying the spectrum makes it easier to identify and quantify the concentration of different components.
The waiting time dependence--which is the delay between the second and the third pulse--provides another experimental "knob" that facilitates identification of molecular species.
In particular it was found that at specific times, unique to each molecular species, parts of the spectrum can disappear due to destructive interference.
The project also resulted in a size-dependent model describing rotational dynamics of antenna-equipped argon clusters.
The theoretical results furnish experimental researchers with tools to interpret and analyze their measurements.
These results are complemented with the simulation code, rotsim2d, that was developed as part of the project.
Most importantly, the software enables simulation of actual experimental spectra.
The code can therefore be used as a component of a fitting procedure to retrieve gas concentrations.
Additionally, the software includes visualization tools that help in understanding different aspects of the theory and consequences thereof.
These theoretical results were validated by measurements of 2DIR spectrum of carbon dioxide asymmetric stretch, demonstrating excellent agreement.
The project also resulted in a design of a unique near-infrared RR2DIR spectrometer employing multiple high-power optical frequency combs and a lock-in Fourier-transform spectrometer.
The results of the project were disseminated at numerous conferences in the form of posters and talks.
The results were also presented at several seminar talks.
The theoretical results on 2DIR spectroscopy were published in two peer-reviewed articles.
Moreover, the work on cavity-enhanced transient absorption spectroscopy, which included dynamics of argon clusters, was published in a peer-reviewed article, and the measurements of CO-N2 spectra, which used our Yb:fiber-based MOPA-OPO, were published in a peer-reviewed article.
