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[en] We present the first interferometric observations at 18.5 GHz of IRS 1 in NGC 7538. These observations include images of the nonmetastable 14NH3 (9, 6) masers with a synthesized beam of 2 arcsec and images of the continuum emission with a synthesized beam of 150 mas. Of the maser emission, the previously known feature near v LSR = -60 km s-1 is spectrally resolved into at least two components and we observe several new maser emission features near v LSR = -57 km s-1. The new maser emission near -57 km s-1 lies 250 ± 90 mas northwest of the maser emission near -60 km s-1. All of the masers are angularly unresolved indicating brightness temperatures TB > 2000 K. We are also able to conclusively associate the ammonia masers with the position of IRS 1. The excitation of these rare ammonia masers is discussed in the context of the rich maser environment of IRS 1.
[en] Comparative characteristics of catalytic activity of electroneutral and positively charged coatings consisting of organoboron nanoparticles with a composition (C2B10H4)n or platinum in ammonia decomposition have been obtained for the first time. The charge on the coatings was created by the supply of a positive voltage of +6 or +10 V. It has been found that, for the same mass of the coatings at 700 K and a pressure of 5 × 10–7 Torr, the rate of ammonia decomposition on a coating consisting of organoboron nanoparticles is 28–43% of the rate of NH3 decomposition on the coating consisting of platinum nanoparticles depending on the voltage supplied to the coatings.
[en] Selenium–gold interaction plays an important role in crystal materials, molecular self-assembly, and pharmacochemistry involving gold. In this paper, we unveiled the mechanism and nature of selenium–gold interaction by studying complexes F2CSe⋯AuY (Y = CN, F, Cl, Br, OH, and CH3). The results showed that the formation of selenium–gold interaction is mainly attributed to the charge transfer from the lone pair of Se atom to the Au—Y anti-bonding orbital. Energy decomposition analysis indicated that the polarization energy is nearly equivalent to or exceeds the electrostatic term in the selenium–gold interaction. Interestingly, the chalcogen–gold interaction becomes stronger with the increase of chalcogen atomic mass in F2CX⋯AuCN (X = O, S, Se, and Te). The cyclic ternary complexes are formed with the introduction of NH3 into F2CSe⋯AuY, in which selenium–gold interaction is weakened and selenium–nitrogen interaction is strengthened due to the synergistic effects.
[en] Full text: The sinthesised by us some complexes of palladium (II) with mercamin (-SCH2 CH2 NH2) were influenced with ammonia in different conditions. Depending of the nature complex and condition of realization of the syhthesis, following complexes: [(Pd2 Cl2(NH3)2 (SCH2CH2NH2)2] (I); [Pd2Br2(NH3)2(SCH2CH2NH2)2] (II) and [Pd2(SCH2CH2NH2)2(NH3)2] Cl2 (III) are received. The results of IRS analysis show, that under the influence of ammonia mercamin can coordinate monodentanto on the sulphur atom (I,II) and bidentanto as a bridge (III). The sulphur atom take place of position in lygand.
[en] We present the detection of metastable inversion lines of ammonia (NH3) from energy levels high above the ground state. We detect these lines in both emission and absorption toward 15 of 17 positions in the central 300 pc of the Galaxy. In total, we observe seven metastable transitions of NH3: (8, 8), (9, 9), (10, 10), (11, 11), (12, 12), (13, 13) and (15, 15), with energies (in Kelvins) ranging from 680 to 2200 K. We also mapped emission from NH3 (8, 8) and (9, 9) in two clouds in the Sgr A complex (M-0.02–0.07 and M-0.13–0.08), and we find that the line emission is concentrated toward the dense centers of these molecular clouds. The rotational temperatures derived from the metastable lines toward M-0.02–0.07 and M-0.13–0.08 and an additional cloud (M0.25+0.01) range from 350 to 450 K. Similarly highly-excited lines of NH3 have previously been observed toward Sgr B2, where gas with kinetic temperatures of ∼600 K had been inferred. Our observations show that the existence of a hot molecular gas component is not unique to Sgr B2, but rather appears common to many Galactic center molecular clouds. In M-0.02–0.07, we find that the hot NH3 contributes ∼10% of the cloud's total NH3 column density, and further, that the hot NH3 in this cloud arises in gas which is extended or uniformly distributed on ∼>10 arcsec scales. We discuss the implications of these constraints upon the nature of this hot gas component. In addition to the detection of hot metastable NH3 line emission, we also detect for the first time emission from nonmetastable inversion transitions of NH3 in both M-0.02–0.07 and M-0.13–0.08
[en] We present results of a survey of CCS, HC3N, and HC5N toward 40 dark cloud cores to search for 'Carbon-Chain-Producing Regions (CCPRs)', where carbon-chain molecules are extremely abundant relative to NH3, as in L1495B, L1521B, L1521E, and the cyanopolyyne peak of TMC-1. We have mainly observed toward cores where the NH3 lines are weak, not detected, or not observed in previous surveys, and the CCS, HC3N, and HC5N lines have been detected toward 17, 17, and 5 sources, respectively. Among them, we have found a CCPR, L492, and its possible candidates, L1517D, L530D, L1147, and L1172B. They all show low abundance ratios of [NH3]/[CCS] (hereafter called the NH3/CCS ratio) indicating the chemical youth. Combining our results with those of previous surveys, we have found a significant variation of the NH3/CCS ratio among dark cloud cores and among molecular cloud complexes. Such a variation is also suggested by the detection rates of carbon-chain molecules. For instance, the NH3/CCS ratios are higher and the detection rates of carbon-chain molecules are lower in the Ophiuchus cores than in the Taurus cores. An origin of these systematic abundance variation is discussed in terms of the difference in the evolutionary stage or the contraction timescale. We have also identified a carbon-chain-rich star-forming core, L483, where intense HC3N and HC5N lines are detected. This is a possible candidate for a core with 'Warm Carbon-Chain Chemistry'.