A5062225026- Nuclear Physics and Applications
- Atmospheric Ozone and Climate
- Geomagnetism and Paleomagnetism Studies
- Spectroscopy and Laser Applications
- Astro and Planetary Science
- Molecular Spectroscopy and Structure
- Atomic and Subatomic Physics Research
- Advanced NMR Techniques and Applications
- Nuclear physics research studies
- Advanced Chemical Physics Studies
- Calibration and Measurement Techniques
- Medical Imaging Techniques and Applications
- Methane Hydrates and Related Phenomena
- Inorganic Fluorides and Related Compounds
- Particle Detector Development and Performance
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Solid-state spectroscopy and crystallography
- Quantum, superfluid, helium dynamics
- Geochemistry and Geologic Mapping
- Spectroscopy Techniques in Biomedical and Chemical Research
- Spacecraft and Cryogenic Technologies
- X-ray Diffraction in Crystallography
- X-ray Spectroscopy and Fluorescence Analysis
- Image Processing and 3D Reconstruction
University College London
2015-2024
Universität Hamburg
2017-2019
Center for Free-Electron Laser Science
2017-2019
Deutsches Elektronen-Synchrotron DESY
2017-2019
Max Planck Institute for the Structure and Dynamics of Matter
2018
Max-Planck-Institut für Kohlenforschung
2015-2017
Max Planck Society
2015
The ExoMol database (www.exomol.com) provides molecular data for spectroscopic studies of hot atmospheres. These are widely used to model atmospheres exoplanets, cool stars and other astronomical objects, as well a variety terrestrial applications. 2024 release reports the current status which contains recommended line lists 91 molecules 224 isotopologues giving total almost 1012 individual transitions. New features include extensive "MARVELization" allow them be high resolutions studies,...
ABSTRACT The MM ro-vibrational line list for methane (12CH4) is presented; covers wavelengths λ > 0.83 μm (wavenumbers up to 12 000 cm−1) and contains over 50 billion transitions between 9155 208 states with total angular momentum J ≤ 60. was generated through solution of the nuclear motion Schrödinger equation using variational program trove an empirically derived potential energy surface (PES) a new high-level ab initio dipole moment surface. PES constructed by fitting energies CH4...
We present an efficient approach for generating highly accurate molecular potential energy surfaces (PESs) using self-correcting, kernel ridge regression (KRR) based machine learning (ML). introduce structure-based sampling to automatically assign nuclear configurations from a pre-defined grid the training and prediction sets, respectively. Accurate high-level ab initio energies are required only points in set, while remaining provided by ML model with negligible computational cost. The...
We present hierarchical machine learning (hML) of highly accurate potential energy surfaces (PESs). Our scheme is based on adding predictions multiple Δ-machine models trained energies and corrections calculated with a hierarchy quantum chemical methods. (semi-)automatic procedure determines the optimal training set size composition each constituent model, simultaneously minimizing computational effort necessary to achieve required accuracy hML PES. Machine are built using kernel ridge...
ABSTRACT A new molecular line list covering wavelengths λ > 1 μm (the 0–10 000 cm−1 range) for the main isotopologue of carbonyl sulphide 16O12C32S is presented. The OCS list, named OYT8, contains almost 2.5 billion transitions between 2.4 million rotation-vibration energy levels with total angular momentum up to J = 223. It suitable high-temperature environments T 2000 K. Line calculations were performed variational nuclear motion code trove in conjunction a highly accurate,...
So called NASA polynomials are widely used in plasma and combustion models to represent the specific heat of molecules as a function temperature. In this work, we compute seven-term for 464 which 44 cations 9 anions; not currently available almost 200 these species. Calculation utilises data provided by ExoMol database, HITRAN diatomic partition functions computed Barklem Collet, JANAF thermodynamic tables. Our results compared against existing polynomial compilations where available, cases...
ABSTRACT A new silicon monoxide (28Si16O) line list covering infrared, visible, and ultraviolet regions called SiOUVenIR is presented. This extends the infrared EBJT ExoMol by including vibronic transitions to $A\, {}^{1}\Pi$ $E\, {}^{1}\Sigma ^{+}$ electronic states. Strong perturbations band system are accurately modelled through treatment of six dark states: $C\, ^{-}$, $D\, {}^{1}\Delta$, $a\, {}^{3}\Sigma ^{+}$, $b\, {}^{3}\Pi$, $e\, $d\, {}^{3}\Delta$. Along with $X\, ground state,...
Two new nine-dimensional potential energy surfaces (PESs) have been generated using high-level \textit{ab initio} theory for the two main isotopologues of methyl chloride, CH$_{3}{}^{35}$Cl and CH$_{3}{}^{37}$Cl. The respective PESs, CBS-35$^{\,\mathrm{HL}}$ CBS-37$^{\,\mathrm{HL}}$, are based on explicitly correlated coupled cluster calculations with extrapolation to complete basis set (CBS) limit, incorporate a range higher-level (HL) additive corrections account core-valence electron...
A new nine-dimensional potential energy surface (PES) for methane has been generated using state-of-the-art \textit{ab initio} theory. The PES is based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set limit and incorporates a range of higher-level additive corrections. These include: core-valence electron correlation, higher-order terms beyond perturbative triples, scalar relativistic effects diagonal Born-Oppenheimer correction....
A novel approach for the state-specific enantiomeric enrichment and spatial separation of enantiomers is presented. Our scheme utilizes techniques from strong-field laser physics---specifically an optical centrifuge in conjunction with a static electric field---to create chiral field defined handedness. Molecular experience unique rotational excitation dynamics, this can be exploited to spatially separate using electrostatic deflection. Notably, rotational-state-specific enhancement its...
New molecular line lists for calcium monohydride ($^{40}$Ca$^{1}$H) and magnesium ($^{24}$Mg$^{1}$H) its minor isotopologues ($^{25}$Mg$^{1}$H $^{26}$Mg$^{1}$H) are presented. The rotation-vibration-electronic (rovibronic) lists, named \texttt{XAB}, consider transitions involving the \X, \A, \BBp\ electronic states in 0--30\,000~cm$^{-1}$ region (wavelengths $\lambda > 0.33$~$\mu$m) suitable temperatures up to 5000 K. A comprehensive analysis of published spectroscopic literature on CaH MgH...
ABSTRACT A comprehensive rotation–vibration (ro–vibrational) line list of thioformaldehyde (1H212C32S) that is applicable for elevated temperatures (${2000}{\, \mathrm{K}}$) presented. The new MOTY covers the 0–8000 cm−1 range (wavelengths $\lambda \gt {1.3}{\, \mu \mathrm{m}})$ and contains around 43.5 billion transitions between 52.3 million states with rotational excitation up to J = 120. Line calculations utilize a newly determined empirically refined potential energy surface (PES) –...
A new nine-dimensional potential energy surface (PES) and dipole moment (DMS) for silane have been generated using high-level \textit{ab initio} theory. The PES, CBS-F12$^{\,\mathrm{HL}}$, reproduces all four fundamental term values $^{28}$SiH$_4$ with sub-wavenumber accuracy, resulting in an overall root-mean-square (rms) error of $0.63{\,}$cm$^{-1}$. PES is based on explicitly correlated coupled cluster calculations extrapolation to the complete basis set limit, incorporates a range...
A variationally computed $^{28}$SiH$_4$ rotation-vibration line list applicable for temperatures up to $T=1200\,$K is presented. The list, called OY2T, considers transitions with rotational excitation $J=42$ in the wavenumber range $0$--$5000\,$cm$^{-1}$ (wavelengths $\lambda> 2\,\mu$m). Just under 62.7 billion have been calculated between 6.1 million energy levels. Rovibrational calculations utilized a new `spectroscopic' potential surface determined by empirical refinement 1452...
ABSTRACT New molecular line lists for lithium hydroxide (6Li16O1H and 7Li16O1H isotopologues) covering wavelengths λ > 1 $\mu$m (0–10 000 cm−1 range) are presented. Each list contains around 300 million transitions between rotation–vibration energy levels with total angular momentum up to J = 95, applicable temperatures T ≈ 3500 K. Line calculations were based on a previously published, high-level ab initio potential surface newly computed dipole moment of the ground $\tilde{X}\,...
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ABSTRACT A theoretical line list for $^{15}$NH$_3$ CoYuTe-15 is presented based on the empirical potential energy and ab initio dipole moments surfaces developed used production of ExoMol CoYuTe $^{14}$NH$_3$. The ro-vibrational levels wavefunctions are computed using variational program trove. ranges up to 10 000 cm$^{-1}$ ($\lambda \ge 1$ μm) contains 929 795 249 transitions between 1 269 961 states with $J\le 30$. should be applicable temperatures $\sim$1000 K. To improve accuracy...
ABSTRACT Silicon dioxide (SiO2) is expected to occur in the atmospheres of hot rocky super-Earth exoplanets but a lack spectroscopic data hampering its possible detection. Here, we present first, comprehensive molecular line list for SiO2. The list, named OYT3, covers wavenumber range 0 – 6000 cm−1 (wavelengths λ > 1.67 μm) and suitable temperatures up T = 3000 K. Almost 33 billion transitions involving 5.69 million rotation–vibration states with rotational excitation J 255 have been...
Any future detection of the calcium monohydroxide radical (CaOH) in stellar and exoplanetary atmospheres will rely on accurate molecular opacity data. Here, we present first comprehensive line list CaOH covering \A--\X\ rotation-vibration-electronic \X--\X\ rotation-vibration bands. The newly computed OYT6 contains over 24.2 billion transitions between 3.2 million energy levels with rotational excitation up to $J=175.5$. It is applicable temperatures $T=3000$~K covers...
Molecular chirality is conventionally understood as space-inversion-symmetry breaking in the equilibrium structure of molecules. Less well known that achiral molecules can be made chiral through extreme rotational excitation. Here, we theoretically demonstrate a clear strategy for generating rotationally induced chirality: An optical centrifuge excites phosphine molecule (${\mathrm{PH}}_{3}$) into cluster states correspond to clockwise ($R$ enantiomer) or anticlockwise ($L$ rotation about...
Potassium hydroxide (KOH) and sodium (NaOH) are expected to occur in the atmospheres of hot rocky super-Earth exoplanets but a lack spectroscopic data is hampering their potential detection. Using robust first-principles methodologies, comprehensive molecular line lists for KOH NaOH that applicable temperatures up $T=3500$ K presented. The OYT4 list covers 0-6000 cm$^{-1}$ (wavelengths $λ> 1.67$ $μ$m) range comprises 38 billion transitions between 7.3 million energy levels with rotational...