Infrared Spectroscopy of Symmetric and Spherical Top Molecules for Space Observation, Volume 2. Pierre-Richard Dahoo

Чтение книги онлайн.

СКАЧАТЬ of the determination of the type of symmetry of the environment in the immediate vicinity of the trapped molecule. The objective is to propose theoretical spectra that match with experimental IR data and hence identify molecules based on transitions and profiles, not only in the gas phase, but also when they are constrained to evolve in an environment, such as a nanocage or a surface.

      Chapter 1 provides a brief overview of the instruments developed and used in the laboratory for the study or observation of molecules, FTIR spectroscopy or laser cavity spectroscopy. An example of embedded instruments such as SPICAM, SPICAV or SOIR aboard an orbiter or a space probe serves to illustrate the instrumental context of space observation and of the international collaboration required to develop measurement instruments, as well as the analysis methods for the identification according to the scientific norms of the molecules that may be present in the probed atmosphere, such as on Mars or Venus during Mars Express and Venus Express missions. Aerosol characterization by spectroscopic ellipsometry is also discussed as a non-standard method. The LIDAR technique, which is used for observing the terrestrial atmosphere, is also described.

      Chapter 2 presents various contributions to the interaction potential energy between the studied molecule and its solid environment, considering the hypothesis of binary interactions: “studied molecule – molecule or atom of the environment”. The quantum “dispersion–repulsion” contribution is modeled by an atom–atom Lennard-Jones potential energy type, while the electrical contribution is modeled by a charge–charge potential energy in the case of clathrate nanocages or multipole–multipole in the case of nanocages of rare gas, fullerene or graphite substrate matrix.

      Chapter 3 provides a description of the substitution model applied to the study of NH₃ in rare gas matrices. An atom–atom potential is used to calculate the interaction between the trapped molecule and its environment. A numerical method is applied to determine the perturbed motions of the molecule. The IR spectral profiles are determined and compared to the experimental spectra. The influence of lattice phonon modes on the shift and width of spectral lines is also discussed.

Chapters 4 and 5 provide a description of the extended substitution model, based on the effect of the local symmetry around the equilibrium position of the molecule in the cage for calculating IR spectra in natural nanocages, such as clathrates and fullerene. This model relies on the substitution model used for building theoretical models in IR spectroscopy in rare gas matrices. The model is applied to CH₄ and NH₃ molecules included in clathrate nanocages (Chapter 4) and NH₃ in a fullerene nanocage.

      In Chapter 6, the theoretical models developed in Volumes 1 and 2 to deal with the adsorption of diatomic and triatomic molecules on a graphite substrate, are applied to the NH₃ molecule in order to determine the IR absorption spectra at a very low temperature. This substrate is often used to model the surface of interstellar dust grains.

      Pierre Richard DAHOO

      Azzedine LAKHLIFI

      June 2021

      Конец ознакомительного фрагмента.

      Текст предоставлен ООО «ЛитРес».

      Прочитайте эту книгу целиком, купив полную легальную версию на ЛитРес.

      Безопасно оплатить книгу можно банковской картой Visa, MasterCard, Maestro, со счета мобильного телефона, с платежного терминала, в салоне МТС или Связной, через PayPal, WebMoney, Яндекс.Деньги, QIWI Кошелек, бонусными картами или другим удобным Вам способом.

/9j/4AAQSkZJRgABAQEBLAEsAAD/7SG0UGhvdG9zaG9wIDMuMAA4QklNBAQAAAAAACUcAgAAAgAA HAJQAAxTYW1pIE1lbmFzY2UcAgUACExheW91dCAxADhCSU0EJQAAAAAAELX3qB9z4ksiHblsoQqR Gig4QklNBDoAAAAAAOUAAAAQAAAAAQAAAAAAC3ByaW50T3V0cHV0AAAABQAAAABQc3RTYm9vbAEA AAAASW50ZWVudW0AAAAASW50ZQAAAABDbHJtAAAAD3ByaW50U2l4dGVlbkJpdGJvb2wAAAAAC3By aW50ZXJOYW1lVEVYVAAAAAEAAAAAAA9wcmludFByb29mU2V0dXBPYmpjAAAADABQAHIAbwBvAGYA IABTAGUAdAB1AHAAAAAAAApwcm9vZlNldHVwAAAAAQAAAABCbHRuZW51bQAAAAxidWlsdGluUHJv b2YAAAAJcHJvb2ZDTVlLADhCSU0EOwAAAAACLQAAABAAAAABAAAAAAAScHJpbnRPdXRwdXRPcHRp b25zAAAAFwAAAABDcHRuYm9vbAAAAAAAQ2xicmJvb2wAAAAAAFJnc01ib29sAAAAAABDcm5DYm9v bAAAAAAAQ250Q2Jvb2wAAAAAAExibHNib29sAAAAAABOZ3R2Ym9vbAAAAAAARW1sRGJ

СКАЧАТЬ