On the nature of interactions in the F2 OXe(…) NCCH3 complex: Is there the Xe(IV)N bond?

Nature of the bonding in isolated XeOF2 molecule and F2 OXe(…) NCCH3 complexes have been studied in the gas phase (0 K) using Quantum Chemical Topology methods. The wave functions have been approximated at the MP2 and DFT levels of calculations, using the APFD, B3LYP, M062X, and B2PLYP functionals with the GD3 dispersion correction. The nature of the formal XeO bond in the XeOF2 monomer depends on the basis set used (all-electron vs. the ecp-28 approximation for Xe). Within the all-electron basis set approach the bond is represented by two bonding attractors, Vi = 1,2 (Xe,O), with total population of about 1.06e and highly delocalized electron density in both bonding basins. No bonding bas…

Complexes of Glycolic Acid with Nitrogen Isolated in Argon Matrices. II : Vibrational Overtone Excitations

Structural changes of glycolic acid (GA) complex with nitrogen induced by selective overtone excitation of the νOH mode were followed in argon matrices using FTIR spectroscopy. For the most stable SSC1 complex present in different trapping sites directly upon deposition site, selective changes in the νOH region were achieved upon near-infrared irradiation. Simultaneously, new conformers of the GA…N2 complex were formed, giving rise to several sets of bands in the νOH and νC=O regions of the spectra. Both position and intensity of new absorptions appeared to be highly sensitive on the wavelength of radiation used, as well as on the annealing of the matrix. Based on theoretical calculations a…

Ab initio molecular dynamics study of overtone excitations in formic acid and its water complex

In this article, we present results from ab initio molecular dynamics simulation of overtone excitation in formic acid monomer and its water complex in the gas phase. For the monomer, a conformation change is observed employing both OH and CH vibrational excitations, which supports experimental findings. In the formic acid–water complex, interconversion also takes place, but it proceeds via hydrogen exchange rather than via intramolecular reaction. Simulations raise a question on effect of quantum and matrix effects to the results. Also, a brief test of different computation methods was done on the system. peerReviewed

Conformation resolved induced infrared activity: trans- and cis-formic acid isolated in solid molecular hydrogen

We report combined experimental and theoretical studies of infrared absorptions induced in solid molecular hydrogen by different conformers of formic acid (HCOOH, FA). FTIR spectra recorded in the H(2) fundamental region (4120-4160 cm(-1)) reveal a number of relatively strong trans-FA induced Q-branch absorptions that are assigned by studying both FA-doped parahydrogen (pH(2)) and normal hydrogen (nH(2)) samples. The induced H(2) absorptions are also studied for HCOOD doped nH(2) crystals for both the trans and cis conformers that show resolvable differences. Samples containing90% of the higher energy cis-HCOOD conformer are produced by in situ IR pumping of the OD stretching overtone of tr…

Raman spectroscopy of glycolic acid complexes with N2

High overtone excitation induced conformational isomerization of glycolic acid – nitrogen complex in an argon matrix was investigated by Raman spectroscopy. The interaction between glycolic acid and nitrogen change the green light (532 nm) induced isomerization processes compared to non-complexed glycolic acid. The 180° rotation around of the Csingle bondC bond and stabilization of carboxyl Odouble bondCsingle bondOsingle bondH dihedral angle to trans position were the main conformational changes observed in the complex of the lowest energy conformer and nitrogen. Interestingly, only one stable light-induced conformational product was observed, which isomerises back to the lowest energy con…

Structure and IR Spectroscopic Properties of HNCO Complexes with SO

FTIR spectroscopy was combined with the matrix isolation technique and quantum chemical calculations with the aim of studying complexes of isocyanic acid with sulfur dioxide. The structures of the HNCO⋯SO2 complexes of 1:1, 1:2 and 2:1 stoichiometry were optimized at the MP2, B3LYPD3, B2PLYPD3 levels of theory with the 6-311++G(3df,3pd) basis set. Five stable 1:1 HNCO⋯SO2 complexes were found. Three of them contain a weak N-H⋯O hydrogen bond, whereas two other structures are stabilized by van der Waals interactions. The analysis of the HNCO/SO2/Ar spectra after deposition indicates that mostly the 1:1 hydrogen-bonded complexes are present in argon matrices, with a small amount of the van de…

Matrix Isolation FTIR and Theoretical Study of Weakly Bound Complexes of Isocyanic Acid with Nitrogen.

Weak complexes of isocyanic acid (HNCO) with nitrogen were studied computationally employing MP2, B2PLYPD3 and B3LYPD3 methods and experimentally by FTIR matrix isolation technique. The results show that HNCO interacts specifically with N2. For the 1:1 stoichiometry, three stable minima were located on the potential energy surface. The most stable of them involves a weak, almost linear hydrogen bond from the NH group of the acid molecule to nitrogen molecule lone pair. Two other structures are bound by van der Waals interactions of N⋯N and C⋯N types. The 1:2 and 2:1 HNCO complexes with nitrogen were computationally tracked as well. Similar types of interactions as in the 1:1 complexes were …

Matrix Isolation and Ab Initio Study of Trans−Trans and Trans−Cis Dimers of Formic Acid

Six trans-trans and five trans-cis dimeric structures of formic acid (HCOOH) are revealed by ab initio calculations. Four trans-trans and two trans-cis dimers are identified in the IR absorption spectra in argon matrices. The trans-cis dimers are obtained by narrow-band IR excitation of the vibrational transitions of the trans-trans dimers. Two trans-trans (tt3 and tt6) and one trans-cis (tc4) dimer are characterized experimentally for the first time. The tunneling decay rates of two trans-cis dimers (tc1 and tc4) are evaluated at different temperatures. A greater lifetime of the trans-cis dimers at elevated temperatures compared to the cis-monomer suggests that the high-energy conformers c…

High vibrational overtone excitation‐induced conformational isomerization of glycolic acid in solid argon matrix

Raman spectroscopy and high-overtone driven isomerization of glyoxylic acid in solid argon

High-overtone induced chemistry of glyoxylic acid isolated in a low-temperature argon matrix was investigated using Raman spectroscopy. The Raman spectra of two most stable conformers of glyoxylic acid are presented. Upon excitation in high overtone vibrational bands by 532 nm irradiation of the lowest energy conformer most abundant in neat deposited sample, the isomerization of glyoxylic acid was observed. The process most plausible proceeds via absorption into the fifth vibrational overtone state of the OH group or its combination with the torsional vibrational transition. The assignment of the fundamental vibrational spectra was assisted by quantum chemical harmonic and anharmonic vibrat…

The nature of inter- and intramolecular interactions in F2OXe…HX (X= F, Cl, Br, I) complexes

Electronic structure of the XeOF2 molecule and its two complexes with HX (X= F, Cl, Br, I) molecules have been studied in the gas phase using quantum chemical topology methods: topological analysis of electron localization function (ELF), electron density, ρ(r), reduced gradient of electron density |RDG(r)| in real space, and symmetry adapted perturbation theory (SAPT) in the Hilbert space. The wave function has been approximated by the MP2 and DFT methods, using APF-D, B3LYP, M062X, and B2PLYP functionals, with the dispersion correction as proposed by Grimme (GD3). For the Xe-F and Xe=O bonds in the isolated XeOF2 molecule, the bonding ELF-localization basins have not been observed. Accord…

”Vähemmän rahaa, enemmän tulosta”

Vibrational spectroscopy of trans and cis deuterated formic acid (HCOOD): Anharmonic calculations and experiments in argon and neon matrices

The absorption spectra of trans and cis conformers of deuterated formic acid (HCOOD) isolated in argon and neon matrices are analyzed in the mid-infrared and near-infrared spectral regions (7900–450 cm � 1 ). Vibrational excitation by narrow-band IR radiation is used to convert the lower-energy trans conformer to the higher-energy cis form. A large number of overtone and combination bands are identified. The results of anharmonic vibrational calculations (CC-VSCF) for both conformers are reported and compared to the experimental spectra.

Miten sinä mittaat oman opetuksesi onnistumista?

Dimers of the Higher-Energy Conformer of Formic Acid: Experimental Observation

We report on the first experimental observation of formic acid dimers composed of two molecules of the higher-energy cis conformer. The cis–cis formic acid dimers are prepared in an argon matrix by selective vibrational excitation of the ground state trans conformer (deuterated form HCOOD) combined with thermal annealing of the matrix at about 30 K. Five cis–cis formic acid dimers are predicted by ab initio calculations (interaction energies from −16.9 to −27.2 kJ molˉ¹), and these structures are used for the assignment of the experimental spectra. Selective vibrational excitation of the obtained cis–cis dimers leads to the formation of several trans–cis dimers, which supports the proposed …

Matrix isolation and quantum chemical studies on the H2O2–SO2complex

Complexation and photochemical reactions of hydrogen peroxide and sulfur dioxide have been studied in solid Ar, Kr and Xe. Complexes between H2O2 and SO2 are characterized using Fourier transform infrared spectroscopy and ab initio calculations. In solid Ar, the H2O2–SO2 complex absorptions are found at wavenumbers of 3572.8, 3518.7, 3511.2, 3504.3, 1340.3, 1280.2 and 1149.9 cm−1. In Kr and Xe matrices, the bonded OH stretching frequencies deviate from the values in Ar, and we propose that the matrix surrounding influences the structure of the H2O2–SO2 complex. UV photolysis of the H2O2–SO2 was also studied in solid Ar, Kr and Xe. This photolysis produces mainly a complex between sulfur tri…

Complexes of Glycolic Acid with Nitrogen Isolated in Argon Matrices. II. Vibrational Overtone Excitations

Structural changes of glycolic acid (GA) complex with nitrogen induced by selective overtone excitation of the &nu

Experimental FTIR-MI and Theoretical Studies of Isocyanic Acid Aggregates

Homoaggregates of isocyanic acid (HNCO) were studied using FTIR spectroscopy combined with a low-temperature matrix isolation technique and quantum chemical calculations. Computationally, the structures of the HNCO dimers and trimers were optimized at the MP2, B3LYPD3 and B2PLYPD3 levels of theory employing the 6-311++G(3df,3pd) basis set. Topological analysis of the electron density (AIM) was used to identify the type of non-covalent interactions in the studied aggregates. Five stable minima were located on the potential energy surface for (HNCO)2, and nine were located on the potential energy surface for (HNCO)3. The most stable dimer (D1) involves a weak, almost linear N-H⋯N hydrog…

Photochemistry of the H2O/CO System Revisited : The HXeOH···CO Complex in a Xenon Matrix

We report on the complex of a noble-gas hydride HXeOH with carbon monoxide. This species is prepared via the annealing-induced H + Xe + OH···CO reaction in a xenon matrix, the OH···CO complexes being produced by VUV photolysis of the H2O···CO complexes. The H–Xe stretching mode of the HXeOH···CO complex absorbs at 1590.3 cm–1 and it is blue-shifted by 12.7 cm–1 from the H–Xe stretching band of HXeOH monomer. The observed blue shift indicates the stabilization of the H–Xe bond upon complexation, which is characteristic of complexes of noble-gas hydrides. The HXeOH···CO species is the first complex of a noble-gas hydride with carbon monoxide and the second observed complex of HXeOH. On the ba…

Photolysis of HCOOH monomer and dimer in solid argon: Raman characterization of in situ formed molecular complexes

Raman spectroscopy combined with the matrix isolation technique was employed to study the 193-nm photodecomposition products of formic acid in an argon matrix. The Raman-active fundamentals belonging to the CO(2) + H(2) and CO + H(2)O photoproducts were assigned. Also, bands due to Fermi resonance between the stretching vibration (nu(1)) and the overtone of the bending mode (2nu(2)) of CO(2) were identified. Both ortho- and para-H(2) molecules were identified from their rotational lines S(0)(1) and S(0)(0), respectively. These bands appeared upon matrix annealing as well as after prolonged photolysis. Additionally, photolysis of FA dimers produces oxalic acid and its secondary photoproducts…

Light-induced opening and closing of the intramolecular hydrogen bond in glyoxylic acid.

The isomerization process of glyoxylic acid (GA) conformers and their complexes with a water molecule were studied in a low temperature argon matrix. The research target was to understand how starting conformation and complexation affects the near-IR (NIR) induced conformer interconversion. The most stable GA conformer (Tc) is characterized by an intramolecular hydrogen bond, and it is found to undergo light-induced conformer interconversion slower than the open (Tt) conformer. Upon complexation with water, the isomerization processes slow down in the case of the Tc conformer, whereas for the Tt-based complex the influence of water is negligible on the isomerization process.

Opiskelijoiden hyvinvointi osana kemian opiskelua

Student Life -konsepti on Jyväskylän yliopistossa vuonna 2009 käyttöön otettu opiskelijoiden kokonaisvaltaista hyvinvointia ja opiskelukykyä tukeva toimintamalli. Jyväskylän yliopiston kemian laitoksella konseptia toteutetaan erityisesti huolehtimalla ensimmäisen vuoden opiskelijoiden opintojen etenemisestä sekä opiskelutaitojen ja opiskeluympäristön kehittämisestä. Student Life -konseptiin liittyvät myös opiskelijoiden hyvinvointineuvojat eli Hyvikset, jotka tarjoavat laitoksella konkreettista matalan kynnyksen ohjausta hyvinvointiin, opiskelukykyyn ja elämän eri osa-alueiden haasteisiin liittyen. Hyvis-toiminta on noussut yhdeksi merkittäväksi tekijäksi opiskelijoiden motivaatiossa ja sit…

Anharmonic Vibrational Spectrum and Experimental Matrix Isolation Study of Thioformic Acid Conformers -- Potential Candidates for Molecular Cloud and Solar System Observations?

Thioformic acid (TFA) is the sulfur analog of formic acid, the simplest organic acid. It has three analogues HCOSH, HCSOH, and HCSSH, each of them having two rotational isomeric (rotameric) forms: trans and cis where the trans form is energetically more stable. In this article, we study computational energetics and anharmonic vibrational spectrum of TFA including overtone and combination vibrations. We also studied experimental photoisomerization and photodecomposition channels of HCOSH molecules with different wavelengths. We suggest that TFA is a potential sulfur containing candidate molecule for interstellar and planetary observations and discuss these in a light of different radiation e…

Conformational-Dependent Photodissociation of Glycolic Acid in an Argon Matrix

Ultraviolet-induced photodissociation and photo-isomerization of the three most stable conformers (SSC, GAC, and AAT) of glycolic acid are investigated in a low-temperature solid argon matrix using FTIR spectroscopy and employing laser radiation with wavelengths of 212 nm, 226 nm, and 230 nm. The present work broadens the wavelength range of photochemical studies of glycolic acid, thus extending the understanding of the overall photochemistry of the compound. The proposed kinetic model for the photodissociation of glycolic acid proceeds from the lowest energy conformer (SSC). The model suggests that ultraviolet light induces isomerization only between the SSC and GAC conformers and between …

Photochemistry of the H2O/CO System Revisited : The HXeOH···CO Complex in a Xenon Matrix

We report on the complex of a noble-gas hydride HXeOH with carbon monoxide. This species is prepared via the annealing-induced H + Xe + OH···CO reaction in a xenon matrix, the OH···CO complexes being produced by VUV photolysis of the H2O···CO complexes. The H–Xe stretching mode of the HXeOH···CO complex absorbs at 1590.3 cm–1 and it is blue-shifted by 12.7 cm–1 from the H–Xe stretching band of HXeOH monomer. The observed blue shift indicates the stabilization of the H–Xe bond upon complexation, which is characteristic of complexes of noble-gas hydrides. The HXeOH···CO species is the first complex of a noble-gas hydride with carbon monoxide and the second observed complex of HXeOH. On the ba…

Complexes of Glycolic Acid with Nitrogen Isolated in Argon Matrices. I : Structures and Thermal Effects

Molecular complexes between glycolic acid and nitrogen were studied in a low-temperature argon matrix with FTIR spectroscopy, and supported by MP2 and BLYPD3 calculations. The calculations indicate 11 and 10 stable complex structures at the MP2 and BLYPD3 levels of theories, respectively. However, only one hydrogen-bonded complex structure involving the most stable SSC conformer of glycolic acid was found experimentally, where the nitrogen molecule is bound with the carboxylic OH group of the SSC conformer. The complex shows a rich site structure variation upon deposition of the matrix in different temperatures and upon annealing experiments, which provide interesting prospects for site-sel…

Vibrational Spectrum of HXeSH revisited : Combined computational and experimental study

Vibrational spectrum of HXeSH embedded in low-temperature matrix is experimentally studied. To support the spectrum interpretation, anharmonic vibrational analysis is performed using different models and basis sets and the data is compared with previous experimental and theoretical analyses. Computations of overtones and combination modes allowed for new band assignments. The HXeSH molecule exhibits high anharmonicity similarly as other molecules from the noble-gas hydride family. Comparison of the employed computational methods shows once again that the modelling of the noble-gas compounds faces theoretical challenges to yield quantitatively reliable results. peerReviewed

Corrigendum to “Light-induced, site-selective isomerization of glyoxylic acid in solid xenon” [Chem. Phys. Lett. 616–617 (2014) 91–97]

Raman spectroscopy of acetic acid monomer and dimers isolated in solid argon

Acetic acid (AA) monomer and its dimers were studied by means of Raman spectroscopy combined with the matrix isolation technique. All fundamental bands of CH3COOH monomer were identified, including the CH3 torsional mode. Additionally, three overtone or combination modes were observed as a result of their enhanced intensities by Fermi resonance (FR). Twenty bands of the cyclic dimer (C2h) were identified and assigned, among which appear all intermolecular modes. Bands due to two different higher energy forms of the dimer were also identified. The experimental assignments are supported by ab initio calculations. Copyright © 2011 John Wiley & Sons, Ltd.

Complexes of HXeY with HX (Y, X = F, Cl, Br, I) : Symmetry-Adapted Perturbation Theory Study and Anharmonic Vibrational Analysis

A comprehensive analysis of the intermolecular interaction energy and anharmonic vibrations of 41 structures of the HXeY· · · HX (X, Y = F, Cl, Br, I) family of noble-gas-compound complexes for all possible combinations of Y and X was conducted. New structures were identified, and their interaction energies were studied by means of symmetry-adapted perturbation theory, up to secondorder corrections: this provided insight into the physical nature of the interaction in the complexes. The energy components were discussed, in connection to anharmonic frequency analysis. The results show that the induction and dispersion corrections were the main driving forces of the interaction, and that their…

Students’ engagement in learning by indigenous knowledge-chemistry lesson

This study was aimed at assessing students’ engagement in an integrated indigenous knowledge-chemistry lesson (IIK-CL) designed using the processes involved in cassava dough production. The paper focuses on the behavioural, emotional and cognitive engagement and their impact on students’ construction of knowledge of the factors affecting rate of chemical reactions. The study was conducted in Swedru senior high school in the Agona East municipality of the Central Region of Ghana. A purposively sampled intact class of 26 students aged between 14 and 18 years formed the study. The control group for this study encompassed also 26 students randomly sampled from the remaining chemistry classes in…

Kemian opetuksen pitää vastata ajan haasteisiin

Asiantuntijuutta, menetelmien hallintaa, laitteiden tuntemusta, ongelmanratkaisun osaamista,uuden oppimisen kykyä,esiintymisen ja vuorovaikutuksen taitoja. Tulevat kemistit tarvitsevat näitä kaikkia. Yliopiston kemian opetuksen on uudistuttava vastaamaan sille esitettyihin haasteisiin. nonPeerReviewed

Computational Structures and SAPT Interaction Energies of HXeSH···H2Y (Y=O or S) Complexes

Ab initio calculations of the structures, vibrational spectra and supermolecular and symmetry-adapted perturbation theory (SAPT) interaction energies of the HXeOH and HXeSH complexes with H2O and H2S molecules are presented. Two minima already reported in the literature were reproduced and ten new ones were found together with some transition states. All complexes show blue shift in Xe&ndash

UV laser induced photolysis of glycolic acid isolated in argon matrices

The photochemistry of matrix-isolated glycolic acid, induced by UV light, was studied by FTIR spectroscopy and B3LYPD3/6-311++G(3df,3pd) calculations. Several decomposition pathways were found to take place upon 212 nm and 226 nm wavelengths irradiation. A number of complexes formed between photoproducts were identified, among them those of formaldehyde with water, carbon monoxide and carbon dioxide as well as the H2O-CO complexes. The structure and spectroscopic assignment of the photoproducts were made comparing the experimental results with the theoretical predictions and available literature data. The observed formation of different complexes indicates various pathways for their formati…

Oppilaiden näkemyksiä luonnontieteiden opettajan auktoriteetistä

Tässä tutkimuksessa selvitettiin oppilaiden näkemyksiä luonnontieteiden opettajan auktoriteetista, sen muodostumisesta ja kehittämisestä. Tutkimus pohjautuu fenomenologis-hermeneuttisen tutkimuksen piirteisiin. Oppilaiden (N = 25) näkemyksiä selvitettiin kyselytutkimuksen avulla ja tutkimusaineisto analysoitiin sekä tilastollisen analyysin että aineistolähtöisen sisällönanalyysin keinoin. Tulosten perusteella auktoriteetti liitettiin osaksi opettajan persoonaa ja asiantuntijuutta. Osaltaan auktoriteetin katsottiin tarkoittavan myös vuorovaikutussuhdetta, jossa opettajalla on oppilasta enemmän valtaa. Auktoriteetin koettiin muodostuvan vuorovaikutussuhteessa, jossa merkittäviä tekijöitä oliv…

Raman spectroscopy of formic acid and its dimers isolated in low temperature argon matrices

Raman spectroscopy combined with matrix isolation technique was employed to study formic acid monomer and its dimers. Nine fundamentals of the HCOOH monomer were identified. Additionally, the OH torsion overtone is observed and it is engaged in Fermi resonance with the δCOH mode. Several bands of the cyclic (C2h) dimer were identified and assigned. The less stable open form (Cs) of the dimer was also present in the experiment. Three intermolecular modes for the cyclic and one mode for the open dimer were found in the low frequency region. The experimental studies were supported by harmonic and anharmonic DFT calculations.

Isolated glyoxylic acid-water 1:1 complexes in low temperature argon matrices

Abstract The 1:1 hydrogen bonded complexes between glyoxylic acid (GA) and water are studied in low temperature argon matrices. Four different complex structures were found in deposited matrices. The lowest energy conformer (T1) of GA was found to form complex, where the water molecule was attached to the opposite side of the intramolecular hydrogen bond in the molecule (T1B). Interestingly, this complex was estimated to be +8.0 kJ mol −1 higher in energy than the most stable structure (T1A), where the water is inserted into the internal hydrogen bond, and also found in solid argon but in smaller abundance. For the second-lowest energy conformer of GA (T2), the two lowest-energy complex str…

Project-Based Education Research Course Supports Exchange-students’ Research Minded Teacher Identity

Project-based education (PBE) gives possibilities for students to work together and feeling of belonging in a community even during distance learning. At the Department of Chemistry, University of Jyväskylä (JYU), a group of exchange students participated in a PBE chemistry teacher education research course online. The goal of the course was to enforce the connection between research on science teaching and acting sustainable in society. This study is based on semi-structured online group interview of the students after this PBE course. The main focus of this investigation was how positive feelings and attitude affect learning. peerReviewed

Matrix-isolation and ab initio study of the complex between formic acid and xenon

Abstract We report on the identification of the complexes of formic acid (FA) and Xe in an argon matrix. The geometries, interaction energies, reaction barriers, and vibrational spectra of the FA⋯Xe complexes are calculated at the MP2 level of theory. The calculations reveal four structures for the trans-FA⋯Xe complex and four structures for the cis-FA⋯Xe complex. In the experiments, two structures of the trans-FA⋯Xe complex are observed after deposition of FA/Xe/Ar matrices, with and without OH⋯Xe interaction (H-bonded and non-H-bonded structures). The cis-FA⋯Xe complex was synthesized by vibrational excitation of the non-H-bonded trans-FA⋯Xe complex. The non-H-bonded and H-bonded structur…

Complexes of Glycolic Acid with Nitrogen Isolated in Argon Matrices. I. Structures and Thermal Effects.

Molecular complexes between glycolic acid and nitrogen were studied in a low-temperature argon matrix with FTIR spectroscopy, and supported by MP2 and BLYPD3 calculations. The calculations indicate 11 and 10 stable complex structures at the MP2 and BLYPD3 levels of theories, respectively. However, only one hydrogen-bonded complex structure involving the most stable SSC conformer of glycolic acid was found experimentally, where the nitrogen molecule is bound with the carboxylic OH group of the SSC conformer. The complex shows a rich site structure variation upon deposition of the matrix in different temperatures and upon annealing experiments, which provide interesting prospects for site-sel…

FTIR matrix isolation and theoretical studies of glycolic acid dimers

Glycolic acid (GA) dimers were studied in low temperature argon matrices by means of FTIR spectroscopy. Experimentally, the dimers were produced when monomeric glycolic acid molecules were thermally mobilized upon annealing of argon matrices at 25–35 K. The experimental spectra observed upon annealing indicate the presence of three different dimer structures. Computationally, MP2 and DFT calculations were used to study the potential dimer species in order to scrutinize the possible dimer structures, their energetics and their spectral features. Altogether 27 local minima were found for dimer structures for the three lowest conformers of glycolic acid considered based on previous studies on …

Light-induced, site-selective isomerization of glyoxylic acid in solid xenon

Abstract The isomerization of glyoxylic acid (GA) and its water complex was studied in a low temperature xenon matrix. The aim of these studies was to understand how xenon environment affects the cis-trans GA interconversion upon near infrared irradiation. In solid xenon, the GA conformers are embedded in two different matrix sites. These show up as different vibrational bands of GA that exhibit different kinetic rates of isomerization. Upon complexation with water, the isomerization process slows down. Xenon matrix appears not to affect energy relaxation process via intramolecular or intermolecular hydrogen bond as compared with previous experiments in an argon.

How can networks help encourage the development and professionalisation of innovative early STEM Education in a changing world?

Maailma muuttuu monimutkaisemmaksi ja vaatii muun muassa STEM*-osaamista ja lukutaitoa oppijoilta, yhteisön jäseniltä ja yhteiskunnilta. Siksi laadukkaalle varhaiselle STEM-koulutukselle tarvitaan laajaa puolustamista. Tässä artikkelissa hahmotellaan, kuinka vaikutusverkostot (joita on muodostettu käsittelemään monimutkaisia sosiaalisia tai ympäristökysymyksiä) voivat edistää varhaisen STEM-koulutuksen kehittämistä ja ammattimaistumista. Sen tavoitteena on tukea alaa kehittäviä oppilaitoksia lisäämään työnsä vaikutusta paremman ja helposti saavutettavan koulutuksen puolesta maailmanlaajuisesti. Tutkittuaan varhaisen STEM-koulutuksen suunniteltuja vaikutuksia nykyisessä kontekstissa esitellä…

Kemiaa – kyllä kiitos!

HXeOBr in a xenon matrix

We report on a new noble-gas molecule HXeOBr prepared in a low-temperature xenon matrix from the HBr and N2O precursors by UV photolysis and thermal annealing. This molecule is assigned with the help of deuteration experiments and ab initio calculations including anharmonic methods. The H−Xe stretching frequency of HXeOBr is observed at 1634 cm−1 , which is larger by 56 cm−1 than the frequency of HXeOH identified previously. The experiments show a higher thermal stability of HXeOBr molecules in a xenon matrix compared to HXeOH. peerReviewed