Колебательно-вращательный спектр высокого разрешения в районе полос 3ν-=SUB=-4-=/SUB=-, ν-=SUB=-2-=/SUB=-+2ν-=SUB=-4-=/SUB=- и 2ν-=SUB=-2-=/SUB=-+ν-=SUB=-4-=/SUB=- молекулы -=SUP=-72-=/SUP=-GeH-=SUB=-4-=/SUB=-

The high-resolution spectrum of the 72GeH4 molecule was recorded on a Bruker IFS 125HR Fourier spectrometer with an optical resolution of 0.003 cm-1. The line positions were analyzed for ten interacting vibrational-rotational bands 3ν4 (1F2, F1, 2F2), v2+ 2ν4 (1E, F1, F2, 2E) and 2ν2+v4 (1F2, F1, 2F2) in the range 2350-2750 cm-1. As a result of the analysis, 1726 experimental lines were identified with the maximum value of the quantum number Jmax = 17; then used in the fitting procedure with parameters of the effective Hamiltonian. The resulting set of 35 spectroscopic parameters describes the vibrational-rotational structure of the spectrum with drms = 7.5 · 10-4 cm-1.

The Massive M31 Cluster G1: Detailed Chemical Abundances from Integrated Light Spectroscopy*

G1, also known as Mayall II, is one of the most massive star clusters in M31. Its mass, ellipticity, and location in the outer halo make it a compelling candidate for a former nuclear star cluster. This paper presents an integrated light abundance analysis of G1, based on a moderately high-resolution (R = 15, 000) spectrum obtained with the High Resolution Spectrograph on the Hobby-Eberly Telescope in 2007 and 2008. To independently determine the metallicity, a moderate resolution (R ∼ 4, 000) spectrum of the calcium-II triplet lines in the near-infrared was also obtained with the Astrophysical Research Consortium’s 3.5-m telescope at Apache Point Observatory. From the high-resolution spectrum, G1 is found to be a moderately metal-poor cluster, with $[\rm {Fe/H}]~=~-0.98\pm 0.05$. G1 also shows signs of α-enhancement (based on Mg, Ca, and Ti) and lacks the s-process enhancements seen in dwarf galaxies (based on comparisons of Y, Ba, and Eu), indicating that it originated in a fairly massive galaxy. Intriguingly, G1 also exhibits signs of Na and Al enhancement, a unique signature of GCs—this suggests that G1’s formation is intimately connected with GC formation. G1’s high [Na/Fe] also extends previous trends with cluster velocity dispersion to an even higher mass regime, implying that higher mass clusters are more able to retain Na-enhanced ejecta. The effects of intracluster abundance spreads are discussed in a subsequent paper. Ultimately, G1’s chemical properties are found to resemble other M31 GCs, though it also shares some similarities with extragalactic nuclear star clusters.

Спектр высокого разрешения полос ν-=SUB=-2-=/SUB=-+ν-=SUB=-4-=/SUB=- (F-=SUB=-1-=/SUB=-,F-=SUB=-2-=/SUB=-) и 2ν-=SUB=-4-=/SUB=- (F-=SUB=-2-=/SUB=-) дейтерированного силана -=SUP=-28-=/SUP=-SiD-=SUB=-4-=/SUB=-

A study of the fine rotational structure of the silane molecule absorption spectrum was carried out for the first time. The high-resolution spectrum of 28SiD4 was recorded in the 1260-1480 cm-1 spectral range the vibrational ν2+ν4 (F1,F2) and 2ν4 (F2) bands were theoretically analyzed. Rotational, centrifugal distortion, tetrahedral splitting and resonance interaction parameters of the upper vibrational states were obtained from the weighted least square fit method. The set parameters obtained reproduces the initial vibrational-rotational structure of the ν2 + ν4 (F1, F2) and 2ν4 (F2) bands with an accuracy of drms = 3.9 · 10-4 cm-1.

Distribution of Characteristic Times: A High-Resolution Spectrum Approach for Visualizing Chemical Relaxation and Resolving Kinetic Parameters of Ionic-Electronic Conducting Ceramic Oxides

Surface exchange coefficient (k) and bulk diffusion coefficient (D) are important properties to evaluate the performance of mixed ionic-electronic conducting (MIEC) ceramic oxides for use in energy conversion devices, such as solid oxide fuel cells. The values of k and D are usually estimated by a non-linear curve fitting procedure based on electrical conductivity relaxation (ECR) measurement. However, the rate-limiting mechanism (or the availability of k and D) and the experimental imperfections (such as flush delay for gaseous composition change, τf) are not reflected explicitly in the time–domain ECR data, and the accuracy of k and D demands a careful sensitivity analysis of the fitting error. Here, the distribution of characteristic times (DCT) converted from time–domain ECR data is proposed to overcome the above challenges. It is demonstrated that, from the DCT spectrum, the rate-limiting mechanism and the effect of τf are easily recognized, and the values of k, D and τf can be determined conjunctly. A strong robustness of determination of k and D is verified using noise-containing ECR data. The DCT spectrum opens up a way towards visible and credible determination of kinetic parameters of MIEC ceramic oxides.

Photometry and high-resolution spectroscopy of comet 21P/Giacobini-Zinner during its 2018 apparition

We report on photometry and high-resolution spectroscopy of the chemically peculiar Jupiter-family comet (hereafter JFC) 21P/Giacobini-Zinner. Comet 21P is a well-known member of the carbon-chain-depleted family, but also displays a depletion of amines. We continuously monitored the comet over more than seven months with the two TRAPPIST telescopes (TN and TS), covering a wide heliocentric distance range from 1.60 au inbound to 2.10 au outbound with a perihelion at 1.01 au on September 10, 2018. We computed and followed the evolution of the dust- (represented by Afρ) and gas-production rates of the daughter species OH, NH, CN, C3, and C2 and their relative abundances to OH and to CN over the cometary orbit. We compared them to those measured in the previous apparitions. The activity of the comet and its water production rate reached a maximum of (3.72 ± 0.07) × 1028 mol s−1 on August 17, 2018 (rh = 1.07 au), 24 days before perihelion. The peak value of A(0)fρ was reached on the same date (1646 ± 13) cm in the red filter. Using a sublimation model for the nucleus, we constrained the active surface of the nucleus using the slow-rotator model. The abundance ratios of the various species are remarkably constant over a wide range of heliocentric distances before and after perihelion, showing a high level of homogeneity of the ices in the surface of the nucleus. The behaviour and level of the activity of the comet is also remarkably similar over the last five orbits. In the coma dust colour, 21P shows reflective gradients similar to JFCs. We obtained a high-resolution spectrum of 21P with UVES at ESO Very Large Telescope one week after perihelion. Using the CN B-X (0, 0) violet band, we measured 12C/13C and 14N/15N isotopic ratios of 100 ± 10 and 145 ± 10, respectively, both in very good agreement with the ratios commonly found in comets. We measured an ortho-para abundance ratio of NH3 of 1.16 ± 0.02, corresponding to a nuclear spin temperature of Tspin = 27 ± 1 K, which is similar to other comets. While the abundance ratios in the gaseous coma reveal a peculiar composition, the isotopic and ortho-to-para ratios appear entirely normal. We performed a dynamical simulation of 21P and found that it is likely a young member of the JFC population. We favour a pristine composition scenario to explain the chemical peculiarities of this comet.

A Novel Single-Channel Arrangement in Chirp Transform Spectrometer for High-Resolution Spectrum Detection

Chirp transform spectrometer (CTS) has become a powerful tool widely used in spectral analysis nowadays. In this paper, a novel single-channel structure of Chirp transform spectrometer for high-resolution spectrum detection is developed. By adding an additional signal source, a mixer, a power divider, and a combiner, one channel of the classical CTS is replaced and the matching problem between the two channels is avoided. The circuit principle and characteristics of the novel single-channel structure are presented. Two simulation models with ideal devices and nonideal devices for the classical two-channel CTS structure and the improved single-channel structure are built to verify the effectiveness of the novel structure. Simulation results show that the time distributions of the obtained compression pulses resulting from the improved structure are the same as that from the classical two-channel CTS. The obtained amplitudes and spectral resolution are almost the same in both structures with ideal devices. The introduced nonideal devices mainly influence the amplitudes of the output pulses. In addition, an experiment with hardware implementation is verified on real chains. The influence of nonideal devices is measured and analyzed. Compared to the classical two-channel structure of CTS, the modified one-channel arrangement avoids the matching problem between different channels and saves devices.

The NH2 scissors band of methylamine

For the first time the ν4 NH2 scissors band has been assigned in a high-resolution infrared spectrum. A rotationally resolved spectrum of methylamine was recorded using two infrared spectroscopic techniques. A White-type multi-pass cell device coupled to the Bruker IFS 125 HR Fourier transform spectrometer was implemented on the AILES beamline at the SOLEIL synchrotron facility and a room-temperature spectrum of the whole band in the region of 1540–1710 cm−1 was recorded with a resolution of 0.001 cm−1. Then, a low-temperature high-resolution spectrum in the 1622.5–1655.6 cm−1 range of Q and R branches of the ν4 band was recorded using a quantum cascade laser spectrometer. Preliminary assignment was carried out in the NH2 scissors band region, and about 2200 transitions for K from 0 to 6 have been assigned for A, B, and E1 symmetry species. The simultaneous fit of assigned lines using a group-theoretical effective Hamiltonian was not successful; instead simple polynomial series expansions were used for each symmetry and K value.

AHLF: ad hoc learning of fragmentation patterns in mass spectra detects post-translationally modified peptides prior to database search

MotivationPublicly available mass spectrometry-based proteomics data has grown exponentially in the recent past. Yet, large scale spectrum-centered analysis usually involves predefined fragmentation features that are limited and prone to be biased. Using deep learning, the decision making for a suitable fragmentation model can be carried out in a data-driven manner.ResultsWe introduce a framework that allows end-to-end training of generic deep learning models on a large collection of high resolution tandem mass spectra. In this case we used 19.2 million labeled spectra from more than a hundred individual PRIDE repositories. In our framework, we developed a representation that captures the complete information of a high-resolution spectrum facilitating a loss-less reduction of the number of features largely independent of the actual resolution. Additionally, it allows us to use common trainable layers, e.g. recurrent or convolutional operations. Specifically, we use a deep network of stacked dilated convolutions to model long range associations between any peaks within a tandem mass spectrum. We exemplify our approach by learning to detect post-translational modifications – in this case, protein phosphorylation – only based on a given mass spectrum in a fully data-driven manner. To the best of our knowledge, this is the first end-to-end trained deep learning model on tandem spectra that is able to ad hoc learn fragmentation patterns in high-resolution spectra. Our approach outperforms the current state-of-the-art in predicting if a mass spectrum originates from a phosphorylated peptide.AvailabilityOur deep learning framework is implemented in tensorflow. The open source code including trained weights is available at gitlab.com/dacs-hpi/[email protected]