324,835 research outputs found
ExoMol line lists - III. An improved hot rotation-vibration line list for HCN and HNC
No full textA revised rotation-vibration line list for the combined hydrogen cyanide (HCN)/hydrogen isocyanide (HNC) system is presented. The line list uses ab initio transition intensities calculated previously and extensive data sets of recently measured experimental energy levels. The resulting line list has significantly more accurate wavelengths than previous ones for these systems. An improved value for the separation between HCN and HNC is adopted, leading to an approximately 25 per cent lower predicted thermal population of HNC as a function of temperature in the key 2000 to 3000 K region. Temperature-dependent partition functions and equilibrium constants are presented. The line lists are validated by comparison with laboratory spectra and are presented in full as supplementary data to the article and at www.exomol.com
COMPUTING SPECTRA OF OPEN-SHELL DIATOMIC MOLECULES WITH DUO
No full text\textsc{Duo} is a program designed to solve a coupled Schr{\"o}dinger
equation for the motion of nuclei of a given diatomic molecule
characterized by an arbitrary set of electronic states.\footnote{ S.N. Yurchenko, L. Lodi, J. Tennyson, and A.V. Stolyarov, \textit{Comput. Phys. Commun.} \textbf{202}, 262 (2016).}
\textsc{Duo} is capable of both refining potential energy curves (by
fitting data to experimental energies or transition frequencies) and producing line lists.
Our most recent results of applying \textsc{Duo} to produce hot line lists for open-shell diatomic molecules include NO,\footnote{A. Wong, S. N. Yurchenko,
P. Bernath, H. S. P. Mueller, S. McConkey, and J. Tennyson, \textit{Mon. Not. R. Astron. Soc.} \textbf{470}, 882 (2017).} SiH,\footnote{S. N. Yurchenko, F. Sinden, L. Lodi, C. Hill, M. N. Gorman, and J. Tennyson, \textit{Mon. Not. R. Astron. Soc.} \textbf{473}, 5324 (2018)} PS and PO,\footnote{L. Prajapat, P. Jagoda, L. Lodi, M. N. Gorman, S. N. Yurchenko, and J. Tennyson, \textit{Mon. Not. R. Astron. Soc.} \textbf{472}, 3648 (2017).} C,\footnote{S. N. Yurchenko, J. Tennyson, and et al, \textit{Mon. Not. R. Astron. Soc.} in preparation (2018).} SN and SH,\footnote{S. N. Yurchenko, W. Bond, M. N. Gorman, L. Lodi, L. K. McKemmish, W. Nunn, R. Shah, and J. Tennyson, \textit{Mon. Not. R. Astron. Soc.} submitted (2018)} and AlH.\footnote{H. Williams, P. C. Leyland, L. Lodi, S. N. Yurchenko, and J. Tennyson, \textit{Mon. Not. R. Astron. Soc.} in preparation (2018).}
The published version of \textsc{Duo} only considers truly bound states.
We are now working on extending \textsc{Duo} to treat quasi-bound or resonance states, or indeed the continuum itself, using the stabilization method.\footnote{A.U. Hazi, H.S. Taylor, \textit{Phys. Rev. A} \textbf{1}, 1109 (1970)} As an illustration, we present simulations of spectra of the quasi-bound system A~ -- X~ of AlH and of the continuum system A~ -- X~ and B~ -- X~ of NaCl
A kinematic analysis of the Yurchenko layout vault
No full textDespite its increasing popularity, there is a paucity of information on the Yurchenko layout compared to other families of vaults. More specifically, little is known if the characteristics of the pre-flight phase of the vault are different between gymnasts from different levels of performance. The purpose of the study is to analyse the characteristics of the pre-flight phase of the Yurchenko layout vault performed by a local National gymnast who competed in the recently concluded 2003 South East Asian Games and to compare the data with that of Olympic level gymnasts. This study seeks to determine if differences exist in the following parameters: a) pre-flight trajectory of the body center of mass (CM), b) shoulder flexion angle and c) the body angle of attack at the end of pre-flight. In addition, the study also seeks to determine if the CM linear velocities at initial horse impact, at end of horse impact, as well as the duration of impact, differ between the levels of performance. Video recording, at 200 Hz, of a female gymnast performing the Yurchenko layout vault was used in the two-dimensional (2D) kinematic analysis. Digitizing was carried out using the PEAK-Motus software to obtain the mechanical variables during the pre-flight and impact phase. In this study, the mean shoulder flexion angles recorded was 160.5 (±9.6) degrees, and this was consistent with those of Olympic gymnasts. The CM trajectory was also observed to be rising during preflight, a pathway required for good vaults. The largest body angle of attack for the local gymnast was only 27.3 degrees which was low compared to Olympic level gymnasts. At initial horse impact subject had a mean CM horizontal velocity of 3.4 (±1.24) m/s. This was reduced by 2.5 m/s to 0. 9 (±0.26) m/s at the end of horse impact. This is low compared to Olympic gymnasts reported in previous studies. The mean vertical velocity at initial horse impact was 1.4 (±0.56) m/s. At horse take-off, the vertical velocity increased by 1.0 m/sto 2.4 (±0.43) m/s. This is comparable to the published data on Olympic gymnasts. The results of the study will provide specific mechanical variables of the pre-flight phase of the Yurchenko vault for coaches to look out for during training. Additionally, the provision of empirical data will enable the coach to use it as the basis for future objective intervention programmes. Specifically, the subject needs to improve on her pre-flight body angle of attack and also to prevent the loss of CM horizontal velocity during horse impact
MOLECULAR LINE LISTS FOR SCANDIUM AND TITANIUM HYDRIDE USING THE DUO PROGRAM
No full textTransition-metal-containing (TMC) molecules often have very complex electronic spectra because of their large number of low-lying, interacting electronic states, of the large multi-reference character of the electronic states and of the large magnitude of spin-orbit and relativistic effects. As a result, fully ab initio calculations of line positions and intensities of TMC molecules have an accuracy which is considerably worse than the one usually achievable for molecules made up by main-group atoms only. In this presentation we report on new theoretical line lists for scandium hydride ScH and titanium hydride TiHfootnote{L. Lodi, S. N. Yurchenko and J. Tennyson, Mol. Phys. (Handy special issue) in press.}. Scandium and titanium are the lightest transition metal atoms and by virtue of their small number of valence electrons are amenable to high-level electronic-structure treatments and serve as ideal benchmark systems. We report for both systems energy curves, dipole curves and various coupling curves (including spin-orbit) characterising their electronic spectra up to about 20 000 cm-1. Curves were obtained using Internally-Contracted Multi Reference Configuration Interaction (IC-MRCI) as implemented in the quantum chemistry package MOLPRO. The curves where used for the solution of the coupled-surface ro-vibronic problem using the in-house program DUO footnote{S. N. Yurchenko, L. Lodi, J. Tennyson and A. V. Stolyarov, Computer Phys. Comms., to be submitted.}. DUO is a newly-developed, general program for the spectroscopy of diatomic molecules and its main functionality will be described.
The resulting line lists for ScH and TiH are made available as part of the Exomol project footnote{J. Tennyson and S. N. Yurchenko, Mon. Not. R. Astr. Soc. 2012, 425, 21. See also www.exomol.com.}.Made available in DSpace on 2016-01-05T20:01:47Z (GMT). No. of bitstreams: 3
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ExoMol line lists-IV. The rotation-vibration spectrum of methane up to 1500 K
No full textA new hot line list is calculated for CH in its ground electronic state. This line list, called 10to10, contains 9.8 billion transitions and should be complete for temperatures up to 1500 K. It covers the wavelengths longer than 1 μm and includes all transitions to upper states with energies below hc · 18 000 cm and rotational excitation up to J = 39. The line list is computed using the eigenvalues and eigenfunctions of CH obtained by variational solution of the Schrödinger equation for the rotation-vibration motion of nuclei employing program TROVE and a new 'spectroscopic' potential energy surface (PES) obtained by refining an ab initio PES (CCSD(T)-F12c/aug-cc-pVQZ) through least-squares fitting to the experimentally derived energies with J = 0-4 and a previously reported ab initio dipole moment surface (CCSD(T)-F12c/aug-cc-pVTZ). Detailed comparisons with other available sources of methane transitions including HITRAN, experimental compilations and other theoretical line lists show that these sources lack transitions both higher temperatures and near-infrared wavelengths. The 10to10 line list is suitable for modelling atmospheres of cool stars and exoplanets. It is available from the CDS data base as well as at www.exomol.com
Rovibrational electric dipole and quadrupole matrix elements for water molecule, in richmol format
No full textRo-vibrational energies, matrix elements of electric dipole and electric quadrupole operators of H216O, calculated using variational approach TROVE, based on spectroscopically-refined potential energy surface and ab initio calculated dipole and quadrupole moment surfaces. The results are stored in HDF5-type file format suitable for the use with richmol program (https://github.com/CFEL-CMI/richmol)
Research articles produced this data:
A. Campargue, S. Kassi, A. Yachmenev, A. Kyuberis, J. Küpper, S. N. Yurchenko, "Observation of electric-quadrupole infrared transitions in water vapor", Phys. Rev. Research 2, 023091 (2020) [10.1103/PhysRevResearch.2.023091]
A. Campargue, A. M. Solodov, A. A. Solodov, A. Yachmenev, S. N. Yurchenko, "Detection of electric-quadrupole transitions in water vapour near 5.4 and 2.5 μm", PCCP 22, 12476-12481 (2020) [10.1039/D0CP01667E]
File "h2o_p48_j40_rovib.h5" contains states up to 15000 cm-1, file "h2o_p48_j40_emax4000_rovib.h5" contains states up to 4000 cm-1 (to be used for Richmol tutorials
Yurchenko Vault's Springboard Phase
No full textIn the Yurchenko(YU)vault, the springboard phase(SB) influences the success and the quality of the vault. From the recent reviews there are no studies concerning the YUSB. The only information about it, are on temporal and velocities data. This study analyzes the linear and angular kinematics of the SB to provide a description of the total and the lower body. The first was studied by the center of mass(COM) velocities and the body’s angle. The second one was analyzed by the hip, knee and ankle angles.
Methods
18 YU of the 2006 Women Italian Championship were filmed using 3 cameras(BASLER 610 100Hz).Each movie was digitized with SIMI Motion.The COM was calculated with the Dempster model.
Results
In SB the horizontal velocity had a decrease of 1,24m/s (mean value mv) between the impact(IMP) and the takeoff(TKO). The vertical velocity at the IMP had a negative value due to the downward direction of the movement (–0,78m/s mv), and at the TKO its was 3,77m/s. The gymnasts hit and leave the SB with a great body’s angle(61° and 96°),so this angle covered a space of 35°(mv) during the SB. The hip is extended of 118°(mv) at the IMP and hyperextend of 195°(mv) at the TKO. The knee had a amortizing and pushing angle of 10° and 30°(mv),respectively. The ankle was flex of 90° at the IMP and its amortizing and pushing angles were 30° and 65°.
Conclusions
In SB the gymnasts exploit the decrease of the COM horizontal velocity to increase the vertical velocity essential to set up the successive phase on the vault, properly.The body’s angle data show that at the IMP, the gymnasts lean back about 30° from the vertical axis as in handspring and Tsukahara vaults.
About the lower body’s angles chain, the gymnasts used the hip joint only to generate the angular momentum and to produce the backward rotation. The knee and ankle joints was used to amortize the hit by the roundoff and then to push for the successive phase
Non-resonant Raman spectra of the methyl radical 12CH3 simulated in variational calculations
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Previous issue date: 2019-06-21We report first-principles variational simulation of the non-resonant Raman spectrum for methyl radical (CH) in the electronic ground state. Calculations are based on a high level \emph{ab initio} potential energy and polarizability tensor surfaces of CH and employ accurate variational treatment of the ro-vibrational dynamics implemented in the general code TROVE [S. N. Yurchenko, W. Thiel, and P. Jensen, {\it J. Mol. Spectrosc.} {\bf 245}, 126--140 (2007); A. Yachmenev and S. N. Yurchenko, {\it J. Chem. Phys.} {\bf 143}, 014105 (2015)]. We extend the capabilities of TROVE towards simulations of the Raman spectra, which can in be applied to arbitrary molecule of moderate size. The simulations for CH are found to be in a good agreement with the available experimental data
Exomol: molecular line list for exoplanets and other atmospheres
No full textThe discovery of extrasolar planets is one of the major scientific
advances of the last two decades. Thousands of planets have now been
detected and astronomers are beginning to characterize their
composition and physical characteristics. To do this requires a huge
quantity of spectroscopic data most of which are not available from
laboratory studies. The ExoMol project [1] is generating a
comprehensive solution to this problem by providing spectroscopic
data on all the molecular transitions of importance in the
atmospheres of exoplanets. These data are widely applicable to other
problems such studies on cool stars, brown dwarfs and circumstellar
environments as well as industrial and technological problems on earth.
ExoMol employs a mixture of first
principles and empirically tuned quantum mechanical methods
to compute comprehensive and very large rotation–vibration and
rovibronic line lists. Results span a variety of closed
(NaH, SiO, PN, NaCl, KCl, CS) and open (BeH, MgH, CaH, AlO, VO) shell
diatomics to triatomics (HCN/HNC, SO, HS, H),
tetratomics (HCO, PH, SO, HO), plus methane [2] and nitric acid [3]. This has led directly to the detection of new species
in the atmospheres of exoplanets [4]. A new comprehensive
data release has just been completed [5]. Progress on and future
prospects of the project will be summarised.
\bibliographystyle{default}
\begin{thebibliography}{5}
\bibitem{jt528} J. Tennyson, S.~N. Yurchenko, Mon. Not. R. astr. Soc., 425, 21, 2012.
\bibitem{jt572} S.~N. Yurchenko, J. Tennyson, J. Bailey, M.~D.~J. Hollis, G Tinetti, Proc. Nat. Acad. Sci., 111, 9379, 2014.
\bibitem{jt614} A.~I. Pavlyuchko, S.~N. Yurchenko, J. Tennyson, Mon. Not. R. astr. Soc., 452, 1702, 2015.
\bibitem{jt629} A. Tsiaras {\it et al}, Astrophys. J., in press.
[5] J. Tennyson {\it et al}, J. Mol. Spectrosc., in press.
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AYTY: A NEW LINE-LIST FOR HOT FORMALDEHYDE
No full textbegin{abstract}
The ExoMol [1] project aims at providing spectroscopic data for key molecules that can be used to characterize the atmospheres of exoplanets and cool stars. Formaldehyde (HCO) is of growing importance in studying and modelling terrestrial atmospheric chemistry and dynamics. It also has relevance in astrophysical phenomena that include interstellar medium abundance, proto-planetary and cometary ice chemistry and masers from extra-galactic sources. However there gaps in currently available absolute intensities and a lack of higher rotational excitations that makes it unfeasible to accurately model high temperature systems such as hot Jupiters. Here we present textbf{AYTY} [2], a new line list for formaldehyde applicable to temperatures up to 1500 . AYTY contains almost 10 million states reaching rotational excitations up to and over 10 billion transitions at up to 10 000 cm. The line list was computed using the variational ro-vibrational solver TROVE with a refined textit{ab-initio} potential energy surface and dipole moment surface.
end{abstract}
begin{thebibliography}{1}
bibitem{jt528}
J.~Tennyson and S.~N. Yurchenko.
newblock {em MNRAS}, 425:21--33, 2012.
bibitem{jt597}
A.~F. Al-Refaie, S.~N. Yurchenko, A.~Yachmenev, and J.~Tennyson.
newblock {em MNRAS}, 2015.
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