Time-resolved Fourier transform infrared emission spectroscopy of CO ∆v = 1 and ∆v = 2 extended bands in the ground X1Σ+ state produced by formamide glow discharge

This paper presents an extension to our knowledge of ∆v = 1 and ∆v = 2 bands of carbon monoxide in the ground state, measured by Fourier transform infrared spectroscopy of glow discharge of formamide-nitrogen mixture. Lines in declared bands are measured up to v = 30 for ∆v = 1 and up to v = 24 for ∆v = 2 band, by use of both InSb and MCT detectors, which have not been measured in the laboratory before. Dunham parameters obtained by fitting our lines are presented as well as comparison to other authors. The paper also demonstrates the interesting impossibility of sufficient population of ∆v = 2 band of CO when only pure CO is used in the glow discharge, instead of formamide-based mixture. Additionally, we present a non-LTE model to describe the intensity pattern of the ∆v = 1 and the ∆v = 2 bands of 12C16O experimental spectra by simulating the corresponding non-LTE vibrational populations of CO

Ariel – a window to the origin of life on early earth?

Is there life beyond Earth? An ideal research program would first ascertain how life on Earth began and then use this as a blueprint for its existence elsewhere. But the origin of life on Earth is still not understood, what then could be the way forward? Upcoming observations of terrestrial exoplanets provide a unique opportunity for answering this fundamental question through the study of other planetary systems. If we are able to see how physical and chemical environments similar to the early Earth evolve we open a window into our own Hadean eon, despite all information from this time being long lost from our planet’s geological record. A careful investigation of the chemistry expected on young exoplanets is therefore necessary, and the preparation of reference materials for spectroscopic observations is of paramount importance. In particular, the deduction of chemical markers identifying specific processes and features in exoplanetary environments, ideally “uniquely”. For instance, prebiotic feedstock molecules, in the form of aerosols and vapours, could be observed in transmission spectra in the near future whilst their surface deposits could be observed from reflectance spectra. The same detection methods also promise to identify particular intermediates of chemical and physical processes known to be prebiotically plausible. Is Ariel truly able to open a window to the past and answer questions concerning the origin of life on our planet and the universe? In this paper, we discuss aspects of prebiotic chemistry that will help in formulating future observational and data interpretation strategies for the Ariel mission. This paper is intended to open a discussion and motivate future detailed laboratory studies of prebiotic processes on young exoplanets and their chemical signatures

Vibrational spectra of La@C<inf>60</inf> and Ce@C<inf>60</inf> endohedral fullerenes: Influence of spin state multiplicity

Endohedral fullerenes with paramagnetic encapsulated atoms are new magnetic materials of interest for numerous applications from medicine to quantum computers. An important phenomenon with endohedral fullerenes is the appearance of new vibrational frequencies not associated with empty fullerenes. The vibrational spectra of the lanthanide endohedral fullerenes La@C and Ce@C in various spin states are calculated using the density functional method. Most of the spectral lines lie in the 300–1600 cm range, and their intensities change dramatically depending on the molecule's symmetry and spin state, which are determined by the encapsulated lanthanide atom. The average frequency shift of the carbon cage vibrations caused by spin transition is only 5 cm . The calculated frequencies of the coupled “metal–carbon cage” vibrations of the lanthanide endohedral fullerenes La@C and Ce@C in various spin states lie in the 10–170 cm range. The computational results for both the frequencies and intensities of the metal–cage modes depend considerably on the spin state. The changes in these vibrational modes are due to the changes in the molecular symmetry and the metal–carbon bond lengths. Such dependence can be used as a basis for controlling the spin state of metallofullerenes by measuring the vibration frequencies in the far-infrared zone, which could be important for nanoelectronics and quantum informatics. 60 60 60 60 -1 -1 -

Physical modellling of air pollutant distribution by laser photoacoustic spectrometry in a wind tunnel

In this work we used the laser photoacoustic detectiopn as an analytical tool for monitoring methanol concentration in a wind tunnel. Methanol was chosen as a tracer substance simulating the pollutants. A simple model of a street canyon together with permeation source of methanol vapour was used in various measurements of cross-section profiles. The distribution an concentration of simulated air pollutions has been studied in the street canyon model as a function of the wind velocity

FIRST APPLICATION OF InAsSb/InAsSbP AND LEADCHALKOGENIDE INFRARED DIODE LASERS FOR PHOTOACOUSTIC DETECTION IN THE 3.2 AND 5μ5\mum REGION.

$^{a}$ S Civis et al., Spectrochimica Acta 56, 2125-2130, 2000. $^{b}$ A. N. Imenkov et al., Review of Scientific Instruments 72, 1988-1992, 2001.Author Institution: J. Heyrovsk\'{y} Institute of Physical Chemistry, Academy of Sciences of the Czech RepublicA new type of semi-conductor lasers with composition InAsSb/InAsSbP are described. The lasers, working in the range of temperatures ($17,5 - 80 K$), are tested as a tool of the high resolution absorption spectroscopy of atmospherically important $species^{a}$. The spectral charachteristics and tunability of the lasers are probed by means of the vibration-rotation lines of the gaseous molecules $C_{2}H_{2}, NH_{3}, OCS, CO, CH_{3}Cl$ and $H_{2}O$. Experimentaly estimated spectral emission linewidths vary in the range 10 - 30 MHz in dependence on the current passing and laser $type^{b}$. Potential applications of the lasers are in the area of analytical chemistry, atmospheric research and kinetics of reactive species. Photoacoustic spectroscopy (PAS) with the InAsSb/InAsSbP and leadchalkogenide tunable infrared diode lasers represents a very promising tool for trace gas monitoring. In this study we present and discuss some results obtained using the $3.2 - 3.6$ and $5\mu$m diode lasers. The results have been obtained with a small and very simple glass photoacoustic cell. The cell consists of a hearing aid microphone (Br\""{u}el \& Kj{\ae}r type 4144/Sennheiser type K6P) and an infrared diode laser. The laser is modulated by means of the amplitude/wavelength modulation at three different resonance frequencies of the cell. The PAS measurements of the dependence of the 2 f signal on the gas mixture pressures yield information on the detection limits and influence of the total pressure in the cell on the amplitude of the photoacoustic signal for different mixtures of the studied gases with air