engleski

Spectra of diatomic molecules: From cold to hot

We shall discuss theoretical aspects of some diatomic molecules spectra in a wide range of temperatures. At ultra-cold conditions (0.1 mK) in a magneto-optical trap translationally and rotationally cold molecules can be produced by two-photon photoassociation of colliding atom pairs. We shall describe one of the scenarios for the formation of cold Cs2 molecules by photoassociation. Cold helium nanodroplets act as a low-temperature cryostat (0.4 K) for the adsorbed Cs2 molecules. Excitation spectra of Cs2 molecules were probed by laser-induced fluorescence between 560 and 690 nm. All observed spectral features are identified by comparison with theoretical spectra simulations. CO molecules are very important in atmosphere investigation, especially the greenhouse gas remediation. We calculated the quantum- mechanical absorption and emission spectra for the Angstrom transition of CO molecule at room temperature (300 K). We studied absorption and thermal emission of cesium vapor superheated in the all-sapphire cell at very high temperatures (1000 - 1200 K). The measured spectra of the Cs2 diffuse band around 710 nm were compared with theoretical simulations using semiquantum approach. In the case of an alkali-helium dimer the semiclassical approximation of spectra simulation is acceptable. We compare the fully quantum-mechanical and the semiclassical approach in the case of K-He spectra in the wide range of temperatures (300 – 3000 K) typical for the atmospheres of brown dwarfs and giant exoplanets.

Spectra, diatomic molecules, ultra-cold, thermal emission

nije evidentirano