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The rotational spectrum of the molecular ion HCNH+ is revisited using double-resonance spectroscopy in an ion trap apparatus, with six transitions measured between 74 and 445 GHz. Due to the cryogenic temperature of the trap, the hyperfine splittings caused by the 14N quadrupolar nucleus were resolved for transitions up to J = 4 ← 3, allowing for a refinement of the spectroscopic parameters previously reported, especially the quadrupole coupling constant eQq. [ABSTRACT FROM AUTHOR]

Two fundamental halocarbon ions, CH2Cl+ and CH3ClH+, were studied in the gas phase using the FELion 22-pole ion trap apparatus and the Free Electron Laser for Infrared eXperiments (FELIX) at Radboud University, Nijmegen (the Netherlands). The vibrational bands of a total of four isotopologs, CH235,37Cl+ and CH335,37ClH+, were observed in selected wavenumber regions between 500 and 2900 cm−1 and then spectroscopically assigned based on the results of anharmonic force field calculations performed at the CCSD(T) level of theory. As the infrared photodissociation spectroscopy scheme employed probes singly Ne-tagged weakly bound complexes, complementary quantum-chemical calculations of selected species were also performed. The impact of tagging on the vibrational spectra of CH2Cl+ and CH3ClH+ is found to be virtually negligible for most bands; for CH3ClH+–Ne, the observations suggest a proton-bound structural arrangement. The experimental band positions as well as the best estimate rotational molecular parameters given in this work provide a solid basis for future spectroscopic studies at high spectral resolutions. [ABSTRACT FROM AUTHOR]

Investigations into bimolecular reaction kinetics probe the details of the underlying potential energy surface (PES), which can help to validate high-level quantum chemical calculations. We utilize a combined linear Paul ion trap with a time-of-flight mass spectrometer to study isotopologue reactions between acetylene cations ( C 2 H 2 + ) and two isomers of C3H4: propyne (HC3H3) and allene (H2C3H2). In a previous study [Schmid et al., Phys. Chem. Chem. Phys. 22, 20303 (2020)],1 we showed that the two isomers of C3H4 have fundamentally different reaction mechanisms. Here, we further explore the calculated PES by isotope substitution. While isotopic substitution of reactants is a standard experimental tool in the investigation of molecular reaction kinetics, the controlled environment of co-trapped, laser-cooled Ca+ ions allows the different isotopic reaction pathways to be followed in greater detail. We report branching ratios for all of the primary products of the different isotopic species. The results validate the previously proposed mechanism: propyne forms a bound reaction complex with C 2 H 2 + , while allene and C 2 H 2 + perform long-range charge exchange only. [ABSTRACT FROM AUTHOR]

The ro-vibrational and pure rotational spectra of the linear ion HC3O+ have been investigated in a 4 K cryogenic ion trap instrument. For this, a novel action spectroscopic technique, called leak-out-spectroscopy (LOS, Schmid et al., J. Phys. Chem. A 2022, 126, 8111), has been utilized and characterized. In total, 45 ro-vibrational transitions within the fundamental band of the ν1 C–H stretching mode were measured with a band center at 3237.132 cm−1, as well as 34 lines from the combination band ν2 + ν4, and 41 lines tentatively identified as the combination band ν2 + ν5 + ν7, interleaved and resonant with ν1. Surprisingly, also two hot bands were detected despite the cryogenic operation temperature. Based on the novel action spectroscopy approach, a new double-resonance rotational measurement scheme was established, consisting of rotational excitation followed by vibrational excitation. Seven rotational transitions were observed between 89 and 180 GHz. Highly accurate spectroscopic parameters were extracted from a fit using all available data. In addition, a pulsed laser system has been employed to record a low resolution vibrational spectrum, in order to demonstrate the compatibility of such lasers with the LOS method. [ABSTRACT FROM AUTHOR]

The rotational spectrum of the molecular ion HCNH+ is revisited using double-resonance spectroscopy in an ion trap apparatus, with six transitions measured between 74 and 445 GHz. Due to the cryogenic temperature of the trap, the hyperfine splittings caused by the 14N quadrupolar nucleus were resolved for transitions up to J = 4 ← 3, allowing for a refinement of the spectroscopic parameters previously reported, especially the quadrupole coupling constant eQq. [ABSTRACT FROM AUTHOR]

Atoms and molecules often react at different rates depending on their internal quantum states. Thus, controlling which internal states are populated can be used to manipulate the reactivity and can lead to a more detailed understanding of reaction mechanisms. We demonstrate this control of reactions by studying the electronically excited state reaction. This reaction is exothermic only if Ca is in one of its excited electronic states. Using laser-cooling and electrodynamic trapping, we cool and trap Ca at millikelvin temperatures for several minutes. We can then change the fraction of time they spend in each of the two excited states by adjusting the detunings of the cooling lasers. This allows us to disentangle the reactions that begin with Ca in the 2P -state from the ones where Ca is in the 2D -state. Using time-of-flight mass spectrometry, we determine independent reaction rate constants for Ca in both electronically excited states. [ABSTRACT FROM AUTHOR]

A cryogenic 22-pole ion trap apparatus is used to probe weakly bound cold CH –He complexes by IR action spectroscopy at 4 K. The infrared photodissociation spectrum of the antisymmetric C–H stretching vibration is recorded in the range of 3102–3139 cm−1. A comparison between the experimental spectrum and a symmetric rotor Hamiltonian indicates that this band is strongly perturbed, but we report here a preliminary set of spectroscopic parameters. [ABSTRACT FROM AUTHOR]

A simple and straightforward synthesis of 5,5′-diamino-4,4′-dinitramino-3,3′-bi-1,2,4-triazole by the selective nitration of 4,4′,5,5′-tetraamino-3,3′-bi-1,2,4-triazole is presented. The interaction of the amino and nitramino groups improves the energetic properties of this functionalized bitriazole. For a deeper investigation of these properties, various nitrogen-rich derivatives were synthesized. The new compounds were investigated and characterized by spectroscopy (1H and 13C NMR, IR, Raman), elemental analysis, mass spectrometry, differential thermal analysis (DTA), X-ray analysis, and impact and friction sensitivities (IS, FS). X-ray analyses were performed and deliver insight into structural characteristics with which the stability of the compounds can be explained. The standard enthalpies of formation were calculated for all compounds at the CBS-4M level of theory, revealing highly positive heats of formation. The energetic performance of the new molecules was predicted with the EXPLO5 V6.02 computer. A small-scale shock reactivity test (SSRT) and a toxicity test gave a first impression of the performance and toxicity of selective compounds. [ABSTRACT FROM AUTHOR]

Triaminotriazolotriazole (TATOT) was used as a nitrogenrich ligand for the formation of the energetic ZnII complexes [ZnCl2(TATOT)2]·H2O (2), [Zn(H2O)(TATOT)3](NO3)2·2H2O (3), and [Zn(TATOT)4](ClO4)2·2H2O (4). The zinc species were prepared in a straightforward and inexpensive synthesis. The complexes 2-4 were structurally characterized using X-ray diffraction. Additionally, the compounds were characterized using elemental analysis and infrared (IR) spectroscopy. Finally, the sensitivities toward thermal and mechanical stimuli were determined by differential thermal analysis (DTA) and BAM (Bundesanstalt für Materialforschung und -prüfung) methods. [ABSTRACT FROM AUTHOR]

Several nitrogen-rich salts of 3-nitramino-4-nitrofurazane and dinitraminoazoxyfurazane were synthesized and characterized by various spectroscopic methods. The crystal structures were determined by low temperature single crystal X-ray diffraction. Moreover the sensitivities toward thermal and mechanical stimuli were determined by differential thermal analysis (DTA) and BAM (Bundesanstalt für Materialforschung und -prüfung) methods. The standard enthalpies of formation were calculated for all compounds at the CBS-4M level of theory, and the energetic performance was predicted with the EXPLO5 V6.02 computer code. [ABSTRACT FROM AUTHOR]

5-Aminohydroximoyl-2-hydroxytetrazole (3) was synthesized in a three-step synthesis from inexpensive starting materials. This novel tetrazole derivative contains two energetic moieties: an N-oxide as well as an aminohydroximoyl group. Various energetic nitrogen-rich salts such as hydroxylammonium (4), guanidinium (5), aminoguanidinium (6), ammonium (7), and triaminoguanidinium (8) were synthesized. Moreover, zwitterionic 5-amidrazonyl-tetrazole-2-oxide monohydrate (9) was synthesized. Compounds4,5,8,9, and10were structurally characterized using single-crystal X-ray diffraction. Additionally, all new compounds were characterized using nuclear magnetic resonance (NMR) and vibrational (infrared [IR], Raman) spectroscopy as well as mass spectrometry and elemental analysis. The thermal behavior was studied using differential thermal analysis (DTA) measurements and the sensitivities of the compounds toward shock, friction, and electrostatic discharge were determined. Finally, the enthalpies of formation were calculated (atomization method, CBS-4 M enthalpies) and several detonation/propulsion parameters computed with the EXPLO5 code. [ABSTRACT FROM AUTHOR]

Sodium 5-cyanotetrazolate sesquihydrate (1) is prepared from sodium azide and two equivalents of sodium cyanide under acidic conditions. 1 is then N-oxidized with Oxone to sodium 5-cyanotetrazolate monohydrate (2). Compound 2 is treated with sodium azide and a Lewis acid to form 5-(1H-tetrazolyl)-2-hydroxytetrazole monohydrate (3). Compound 3 can be deprotonated twice by various bases to give ionic derivatives such as the bis(hydroxylammonium) (4), bis(hydrazinium) (6), bis(-guanidinium) (7), bis(aminoguanidinium) (8), bis(ammonium) (9), and diaminouronium (11) salt. In addition, compound 3 can only be deprotonated once, as demonstrated by the hydroxylammonium (4) and triaminoguanidinium (10) salts. Compounds 2-5 and 10-11 are structurally characterized by singlecrystal X-ray diffraction. Additionally, compounds 2-11 are characterized by using NMR and vibrational (IR, Raman) spectroscopy as well as mass spectrometry and elemental analysis. Their thermal behaviors are studied from differential thermal analysis measurements, and the sensitivities of the compounds toward shock, friction, and electrostatic discharge are determined. In addition, the heats of formation are calculated (atomization method, CBS-4M enthalpies), and several detonation/ propulsion parameters are computed with the EXPLO5 code. [ABSTRACT FROM AUTHOR]

Sodium 5-cyanotetrazolate sesquihydrate ( 1) was prepared from sodium azide and two equivalents of sodium cyanide under acidic conditions. Sodium 5-cyanotetrazolate sesquihydrate ( 1) reacts with hydroxylammonium chloride to form 5-aminohydroximoyl tetrazole ( 2). 5-Aminohydroximoyl tetrazole ( 2) is treated with sodium nitrite and hydrochloric acid to form 5-chlorohydroximoyl-tetrazole ( 3). The chloride azide exchange yields 5-azidohydroximoyl-tetrazole monohydrate ( 4). When compound 4 is treated with hydrochloric acid, 5-(1 H-tetrazolyl)-1-hydroxytetrazole ( 5) is obtained in good yield. Compound 5 can be deprotonated twice by various bases. Different ionic derivatives such as bis(hydroxylammonium) ( 6), bis(hydrazinium) ( 7), bis(guanidinium) ( 8), bis(aminoguanidinium) ( 9), bis(ammonium) ( 10), and diaminouronium ( 11) 5-(1-oxidotetrazolyl)-tetrazolate were synthesized and characterized. With respect to energetic use salts 6 and 7 are most relevant. Compounds 3- 9 and 11 were characterized using low temperature single-crystal X-ray diffraction. All compounds were investigated by NMR and vibrational (IR, Raman) spectroscopy, mass spectrometry and elemental analysis. The thermal properties were determined by differential scanning calorimetry (DSC). The sensitivities towards impact ( 4: 4 J, 5: 40 J, 6: 12 J, 7: 40 J), friction: ( 4: 60 N, 5: 240 N, 6: 216 N, 7: 240 N), and electrical discharge ( 5: 0.40 J, 6: 0.75 J, 7: 0.75 J), were investigated using BAM standards and a small scale electrostatic discharge tester. The detonation parameters of 5- 7 were calculated using the EXPLO5.06 code and calculated (CBS-4 M) enthalpy of formation values. [ABSTRACT FROM AUTHOR]

Innovative materials for phosphor converted white light-emitting diodes are in high demand owing to the huge potential of the light-emitting diode technology to reduce energy consumption worldwide. As the primary blue diode is already highly optimized, the conversion phosphors are of crucial importance for any further improvements. We report on the discovery of the high performance red phosphor Sr[Li2Al2O2N2]:Eu2+ meeting all requirements for a phosphor's optical properties. It combines the optimal spectral position for a red phosphor, as defined in the 2016 Research & Development-plan of the United States government, with an exceptionally small spectral full width at half maximum and excellent thermal stability. A white mid-power phosphor-converted light-emitting diode prototype utilising Sr[Li2Al2O2N2]:Eu2+ shows an increase of 16% in luminous efficacy compared to currently available commercial high colour-rendering phosphor-converted light-emitting diodes, while retaining excellent high colour rendition. This phosphor enables a big leap in energy efficiency of white emitting phosphor-converted light-emitting-diodes. Developing innovative materials for reduced energy consumption in phosphor converted white light-emitting diodes remains a challenge. Here, the authors report a narrow band red-emitting oxonitride material with a highly symmetrical Sr2 + coordination for energy efficient white light-emitting diodes. [ABSTRACT FROM AUTHOR]