Spectroscopic Constants and Anharmonic Vibrational Frequencies of C(O)OC, c-C2O2 and Their Silicon-Containing Analogues.

Comets are likely to contain various carbon oxide molecules potentially including C(O)OC and c-C2O2 on their surfaces and comae, as well as their silicon-substituted analogues possibly playing a role in the formation of interstellar dust grains. In this work, high-level quantum chemical data are provided to support such potential future astrophysical detection through the generation of predicted rovibrational data. Laboratory-based chemistry would also benefit from such aforementioned computational benchmarking considering these molecules' historic computational and experimental elusiveness. Coupled-cluster singles, doubles, and perturbative triples, the F12b formalism, and the cc-pCVTZ-F12 basis set garner the rapid, yet highly trusted F12-TcCR level of theory leveraged presently. This current work points to all four molecules' strong IR activity, coupled with large intensities, thus suggesting the potential for JWST detection. Although Si(O)OSi possesses a permanent dipole moment significantly larger than those of the other molecules of present interest, the significant abundance of the potential precursor carbon monoxide suggests that the dicarbon dioxide molecules may yet be observable in the microwave region of the electromagnetic spectrum. Thus, this present work details the likely existence and detectability of these four cyclic molecules, providing updated implications compared to previous work performed both experimentally and computationally.

Rotational and Vibrational Signatures of Astrophyscially relevant Gas-Phase Stereo-isomeric Species of Proteinogenic Amino acid Leucine.

The search for life-supporting molecules in outer space is an ever-growing endeavour. Towards this, the computational chemistry supporting the astronomical spectroscopic observations is becoming a valuable tool to unravel the complex chemical network in interstellar medium (ISM). In the present work, quantum-mechanical computations, accounting for anharmonic effects, are performed to obtain the rotational and vibrational line-data for the gas-phase conformers of proteinogenic amino acid Leucine and its isomeric species predicted to be involved in its stereoinversion under the extreme environment of ISM. These species exhibit diverse chemistry including branched skeleton and zwitterionic ammonium ylides. A few of the species have significantly high dipole moment, which can act as tracer for the conformers of Leucine having low dipole moment. Besides this, the species, which are terrestrially less stable, can be of significant importance to the astronomers. Notably, the spectral database generated in this work can assist in the detection of proteinogenic Leucine and its isomeric species in different regions of ISM.

Laboratory Observation of, Astrochemical Search for, and Structure of Elusive Erythrulose in the Interstellar Medium.

Rotational spectroscopy provides the most powerful means of identifying molecules of biological interest in the interstellar medium (ISM), but despite their importance, the detection of carbohydrates has remained rather elusive. Here, we present a comprehensive Fourier transform rotational spectroscopic study of elusive erythrulose, a sugar building block likely to be present in the ISM, employing a novel method of transferring the hygroscopic oily carbohydrate into the gas phase. The high sensitivity of the experiment allowed the rotational spectra of all monosubstituted isotopologue species of 13C-12C3H8O4 to be recorded, which, together with quantum chemical calculations, enabled us to determine their equilibrium geometries (reSE) with great precision. Searches employing the new experimental data for erythrulose have been undertaken in different ISM regions, so far including the cold areas Barnard 1, the pre-stellar core TMC-1, Sagittarius B2. Although no lines of erythrulose were found, this data will serve to enable future searches and possible detections in other ISM regions.

Central serous chorioretinopathy secondary to solar retinopathy: an unusual presentation.

Solar retinopathy (SR) results from unprotected solar eclipse viewing and also from gazing at the sun for a long duration. It has been known for a long that direct viewing of the sun causes visual disruption. Usually, there is a disruption of the inner segment-outer segment junction, but an association of central serous chorioretinopathy (CSCR) with SR is quite rare. We report a case of CSCR associated with solar eclipse viewing.

A novel Chebyshev neural network approach for solving singular arbitrary order Lane-Emden equation arising in astrophysics.

The motivation of this investigation is to develop a single-layer Chebyshev Neural Network (ChNN) model to handle singular fractional (arbitrary)-order Lane-Emden type equations. These equations are well-known application problems of astrophysics and quantum mechanics. Fractional Lane-Emden equations are singular so it is very difficult to solve analytically. Thus, an efficient method is required to handle the above equations. Here, our main aim is to use a single-layer ChNN model for solving fractional Lane-Emden equations. ChNN model is one kind of Functional Link Neural Network (FLNN) in which the hidden layer is replaced by a functional expansion block of the input pattern using orthogonalshifted Chebyshev polynomials (SChP). Thus, the network parameters of ChNN are less than the Multi-Layer Artificial Neural Network (MLANN). We have considered factional-order singular nonlinear problems of astrophysics to show the computational effort of the proposed method. Back Propagation algorithm of the unsupervised version has been considered for minimizing the error function and updating the weights of the ChNN model. Computed results are displayed in terms of tables and graphs.

Photodestruction of Diatomic Molecular Ions: Laboratory and Astrophysical Application.

In this work, the processes of photodissociation of some diatomic molecular ions are investigated. The partial photodissociation cross-sections for the individual rovibrational states of the diatomic molecular ions, which involves alkali metals, as well as corresponding data on molecular species and molecular state characterizations, are calculated. Also, the average cross-section and the corresponding spectral absorption rate coefficients for those small molecules are presented in tabulated form as a function of wavelengths and temperatures. The presented results can be of interest for laboratory plasmas as well as for the research of chemistry of different stellar objects with various astrophysical plasmas.

[When science and music meet]. / Quand science et musique se rencontrent.

TITLE: Quand science et musique se rencontrent. ABSTRACT: Musique et sciences ont souvent été liées dans l'histoire de la musique. Cependant, rares sont les compositeurs qui ont eu l'occasion d'interagir avec un scientifique pour s'imprégner de son travail et l'utiliser comme source d'inspiration. Le projet Muse-IC se propose de donner cette opportunité à des compositeurs d'aujourd'hui, en leur commandant une œuvre inspirée par une découverte scientifique récente. À la suite d'un double appel réalisé auprès de chercheurs et de compositeurs, des compositeurs se sont immergés dans l'univers scientifique de chercheurs afin de repousser les limites de leur démarche créative. Entre 2017 et 2019, six compositeurs ont écrit une pièce inspirée de la découverte d'un chercheur avec lequel ils ont interagit directement. L'aboutissement de ce projet a donné lieu à une conférence-concert à la salle Cortot, à Paris, une occasion unique de sensibiliser le public à l'importance de la recherche fondamentale au travers d'une rencontre originale entre compositeurs, musiciens et chercheurs.

A half century of infrared astronomy - A personal recollection of the footprints in Japan.

Since the new era of infrared astronomy was opened by the Two Micron Sky Survey by Neugebauer et al. in the early 1960s, about a half century has passed. During this time, observations have expanded rapidly and widely, to almost every field of astronomy, to reveal new perspectives on the universe. As a result, infrared astronomy has become one of the major branches of astronomy, along with optical, radio, X-ray as well as high-energy particle astronomy. In Japan, we started our infrared astronomical activities at a rather early time, under relatively poor technical and environmental conditions, and using somewhat unconventional methods to overcome these difficulties. Here, a brief survey is presented of developments concerning infrared astronomy during the past half century, while mainly recollecting our footprints in the stream of world activities.

Introductory lecture: advances in ion spectroscopy: from astrophysics to biology.

This introduction provides a historical context for the development of ion spectroscopy over the past half century by following the evolution of experimental methods to the present state-of-the-art. Rather than attempt a comprehensive review, we focus on how early work on small ions, carried out with fluorescence, direct absorption, and photoelectron spectroscopy, evolved into powerful technologies that can now address complex chemical problems ranging from catalysis to biophysics. One of these developments is the incorporation of cooling and temperature control to enable the general application of "messenger tagging" vibrational spectroscopy, first carried out using ionized supersonic jets and then with buffer gas cooling in radiofrequency ion traps. Some key advances in the application of time-resolved pump-probe techniques to follow ultrafast dynamics are also discussed, as are significant benchmarks in the refinement of ion mobility to allow spectroscopic investigation of large biopolymers with well-defined shapes. We close with a few remarks on challenges and opportunities to explore molecular level mechanics that drive macroscopic behavior.

Likelihood analysis of small field polynomial models of inflation yielding a high Tensor-to-Scalar ratio.

Inflationary potentials, with Planckian field excursions, described by a 6th degree polynomial are studied. We solve the Mukhanov-Sasaki equations exactly and employ a probabilistic approach as well as multinomial fitting to analyse the results. We identify the most likely models which yield a tensor-to-scalar ratio r = 0.01 in addition to currently allowed Cosmic Microwave Background (CMB) spectrum and observables. Additionally, we find a significant inter-dependence of CMB observables in these models. This might be an important effect for future analyses, since the different moments of the primordial power spectrum are taken to be independent in the usual Markov chain Monte Carlo methods.

'One common matter' in Descartes' physics: the Cartesian concepts of matter quantities, weight and gravity.

It is common to assume that Descartes did not have a conception of an object's matter density independently of its size, but this is a rather incomplete assessment of the early modern natural philosopher's theory. Key to our understanding of Descartes's physics is a consideration of the ratios between the quantities of the different types of matter in which an object consists. As these ratios determine the degree of an object's porosity and elasticity, they also affect in Descartes's theory the phenomena of gravity and weight.

Melchior Inchofer, Giordano Bruno, and the soul of the world.

Following Galileo's trial of 1633, the Jesuit theologian Melchior Inchofer, author of the most negative reports used by the Roman Inquisition against Galileo, repudiated the Copernicans for the 'heresy' of the soul of the world (anima mundi), in an unpublished manuscript. I show that Inchofer's arguments applied far more to the beliefs of Giordano Bruno than to those of Galileo. Since antiquity, various Christian authorities had repudiated several beliefs about the anima mundi as 'heretical', hence I review their critiques against Pythagoras, Origen, and Peter Abelard, for allegedly asserting animistic beliefs about the Earth, or a universal spirit, or that souls move the heavenly bodies. Still, in the Renaissance such beliefs were defended by several advocates of Copernicus, including Bruno, William Gilbert, Johannes Kepler, and Philips Lansbergen, who all claimed that Earth moves because it has a soul. By comparing Inchofer's works and some of the Roman Inquisition's earlier censures against Bruno, I argue that the repudiation by many prominent Catholic theologians of pagan notions of the anima mundi as heretical contributed partly to the later theological opposition to the Copernicans.