Teljes rezgési-forgási színképek meghatározása = Determination of complete rotational-vibrational spectra

38 angol nyelvű és egy magyar nyelvű közlemény jelent meg, egy-egy a Nature (2008), a Chem. Eur. J. (2010) és a Phys. Rev. Lett. (2012) nagy hatástényezőjű folyóiratokban. A közlemények összesített impakt faktora több mint 100, a közleményekre már eddig több mint 250 hivatkozás érkezett. Komoly előrelépést értünk el a módszerfejlesztésekben, különös tekintettel a magmozgásoknak a kvantumkémia eszköztárával történő számítására. Ki- illetve továbbfejlesztettük a DOPI (discrete variable representation–orthogonal coordinates–product basis–iterative diagonalization), a DEWE (discrete variable representation–Eckart-Watson Hamiltonian–exact potential), a GENIUSH (general nuclear motion code with numerical, internal coordinate, user specified Hamiltonian), a MARVEL (measured active rotational-vibrational energy levels) és a NEAT (network of reaction enthalpis leading to atom-based thermochmistry) programrendszereket, bevezettük a spektroszkópiai hálózatok fogalmát, a rezgési-forgási hullámfüggvények értelmezésére kidolgoztuk a NMD (normal-mode decomposition) és RRD (rigid-rotor decomposition) eljárásokat. A kifejlesztett algoritmusokat és programrendszereket alkalmaztuk a spektroszkópiában és a termokémiában, különösen fontos szerkezeti és dinamikai eredményeket értünk el a H3+, H2O, NH3, CH4 és H2CCO molekulák és izotopológjaik kapcsán. Új eljárást dolgoztunk ki, mely a kísérleti, kvantumkémiai és információtechnológiai ismeretek kombinálásával segíti a molekulaspektroszkópiát. | 38 English and one Hungarian articles were published, one each in the high impact factor journals Nature (2008), Chem. Eur. J. (2010), and Phys. Rev. Lett. (2012). The cumulative impact of the publications is more than 100 and these articles have received more than 250 citations. Significant progress was made in our method development efforts, with emphasis on quantum chemical nuclear motion computations. We further developed our program systems allowing nuclear motion computations, including DOPI (discrete variable representation–orthogonal coordinates – product basis – iterative diagonalization), DEWE (discrete variable representation–Eckart-Watson Hamiltonian–exact potential), GENIUSH (general nuclear motion code with numerical, internal coordinate, user specified Hamiltonian), MARVEL (measured active rotational-vibrational energy levels), and NEAT (network of reaction enthalpies leading to atom-based thermochmistry), introduced the notion of spectroscopic networks, and to understand rovibrational wavefunctions we developed the normal-mode decomposition (NMD) and rigid-rotor decomposition (RRD) protocols. The algorithms and program systems developed were employed in computational molecular spectroscopy and thermochemistry, important structural and dynamical results were generated for H3+, H2O, NH3, CH4, H2CCO, and their isotopologues. A new approach combining experiment, quantum theory, and information technology, to high-resolution molecular spectroscopy was developed

Kis molekulák adatbázis alapú teljes spektroszkópiája = Database approach to the complete spectroscopy of small molecules

A Jonathan Tennyson professzorral (UCL, London, UK) csoportjával kezdeményezett kutatási együttműködés a számítógépes nagyfelbontású molekulaspektroszkópia területén valósult meg. A közös kutatómunka négy publikációt eredményezett, mindegyik a víz spektroszkópiájára vonatkozott, mely a legfontosabb földi üvegház hatású gáz. Az együttműködés keretében minden eddiginél pontosabb ab initio szemiglobális potenciális energia (PES) és dipólusmomentum (DMS) felületeket készítettünk a víz molekula elektron alapállapotára. Az azóta már többek által felhasznált PES neve CVRQD, míg a DMS-é CVR, ahol CV a törzs- és vegyértékelektronok korrelált mozgásának számítására utal, míg R a relativisztikus korrekcióra. A PES számítása során kvantumelektrodinamikai (QED) és diagonális Born-Oppenheimer korrekciók (DBOC) számítására is sor került. Egy további közleményben egy minden eddiginél pontosabb PES-t közöltünk a H2(16)O, H2(17)O és H2(18)O izotopológokra, mely a kísérleti adatokhoz történt illesztésen alapult. A MARVEL (Measured Active Rotational-Vibrational Energy Levels) algoritmus elkészítésében is közreműködött Tennyson professzor. | The research collaboration proposed with the group of Professor Jonathan Tennyson (UCL, London, UK) concerned the area of computational high-resolution molecular spectroscopy. The joint research resulted in four publications, all related to the spectroscopy of the water molecule, the most important greenhouse gas on Earth. Within the collaboration we developed ab initio semiglobal potential energy (PES) and dipole moment (DMS) surfaces of unprecedented accuracy for the ground electronic state of the water molecule. These PES and DMS surfaces, which have been used by many others since their development, are called CVRQD and CVR, respectively, where CV refers to the correlated motion electronic structure computations involving core and valence electrons, while R stand for the inclusion of relativistic effects. During the computation of the PES we considered quantum electrodynamic (QED) and diagonal Born-Oppenheimer (DBOC) effects, as well. In another publication we presented theup to now most accurate empirical PES for the isotopologues H2(16)O, H2(17)O, and H2(18)O, whose development was based on a refinement to existing observed data. Development of the MARVEL (Measured Active Rotational-Vibrational Energy Levels) procedure was also performed in collaboration with Professor Tennyson

Empirical rovibrational energy levels for nitrous oxide

A survey of the huge number of measured rovibrational transitions of the ¹⁴N₂ ¹⁶O isotopologue of nitrous oxide is performed which either confirms the positions, the assignments, and the uncertainties of the measurements or refutes at least one of them. Data from 95 literature sources are analyzed and their assignments adjusted to a uniform set of polyads and associated counting numbers. This is an important result of the present study and this canonical set of vibrational state assignments is recommended for future studies. The adjusted list of 67 930 transitions (43 246 unique ones) then underwent a thorough Marvel (Measured Active Rotational–Vibrational Energy Levels) analysis, yielding 17 561 empirical rovibrational energy levels. Uncertainties for these levels are determined using a newly implemented bootstrap approach. The bootstrap uncertainties indicate that the uncertainties for about 1.5% of the energy levels had to be increased significantly, often by more than 10 times compared to previous level uncertainty estimates. This study yields empirical values for 78 band origins of ¹⁴N₂ ¹⁶O for states with ℓ = O where ℓ is the vibrational angular momentum quantum number. The measured transitions and the empirical energy levels are compared to the SISAM and the recent NOSL-296 line lists with the result that while the overall agreement is good, there are still a number of issues requiring further careful experimental and modeling studies

Experimental energy levels and partition function of the 12^{12}C2_2 molecule

The carbon dimer, the $^{12}$C$_2$ molecule, is ubiquitous in astronomical environments. Experimental-quality rovibronic energy levels are reported for $^{12}$C$_2$, based on rovibronic transitions measured for and among its singlet, triplet, and quintet electronic states, reported in 42 publications. The determination utilizes the Measured Active Rotational-Vibrational Energy Levels (MARVEL) technique. The 23,343 transitions measured experimentally and validated within this study determine 5,699 rovibronic energy levels, 1,325, 4,309, and 65 levels for the singlet, triplet, and quintet states investigated, respectively. The MARVEL analysis provides rovibronic energies for six singlet, six triplet, and two quintet electronic states. For example, the lowest measurable energy level of the \astate\ state, corresponding to the $J=2$ total angular momentum quantum number and the $F_1$ spin-multiplet component, is 603.817(5) \cm. This well-determined energy difference should facilitate observations of singlet--triplet intercombination lines which are thought to occur in the interstellar medium and comets. The large number of highly accurate and clearly labeled transitions that can be derived by combining MARVEL energy levels with computed temperature-dependent intensities should help a number of astrophysical observations as well as corresponding laboratory measurements. The experimental rovibronic energy levels, augmented, where needed, with {\it ab initio} variational ones based on empirically adjusted and spin-orbit coupled potential energy curves obtained using the \Duo\ code, are used to obtain a highly accurate partition function, and related thermodynamic data, for $^{12}$C$_2$ up to 4,000 K.Comment: ApJ Supplements (in press), 48 page

MARVEL analysis of the measured high-resolution rovibrational spectra of C2H2

Rotation-vibration energy levels are determined for the electronic ground state of the acetylene molecule, $^{12}$C$_2$H$_2$, using the Measured Active Rotational-Vibrational Energy Levels (MARVEL) technique. 37,813 measured transitions from 61 publications are considered. The distinct components of the spectroscopic network linking ortho and para states are considered separately. The 20,717 ortho and 17,096 para transitions measured experimentally are used to determine 6013 ortho and 5200 para energy levels. The MARVEL results are compared with alternative compilations based on the use of effective Hamiltonians.Comment: 55 pages, 8 figures, JQSRT, 201

MARVEL analysis of high‐resolution rovibrational spectra of 13 {}^{13} C16 {}^{16} O2 {}_2

A set of empirical rovibrational energy levels, obtained through the MARVEL (measured active rotational‐vibrational energy levels) procedure, is presented for the CO isotopologue of carbon dioxide. This procedure begins with the collection and analysis of experimental rovibrational transitions from the literature, allowing for a comprehensive review of the literature on the high‐resolution spectroscopy of CO, which is also presented. A total of 60 sources out of more than 750 checked provided 14,101 uniquely measured and assigned rovibrational transitions in the wavenumber range of 579–13,735 cm. This is followed by a weighted least‐squares refinement yielding the energy levels of the states involved in the measured transitions. Altogether 6318 empirical rovibrational energies have been determined for CO. Finally, estimates have been given for the uncertainties of the empirical energies, based on the experimental uncertainties of the transitions. The detailed analysis of the lines and the spectroscopic network built from them, as well as the uncertainty estimates, all serve to pinpoint possible errors in the experimental data, such as typos, misassignment of quantum numbers, and misidentifications. Errors found in the literature data were corrected before including them in the final MARVEL dataset and analysis

MARVEL analysis of high-resolution rovibrational spectra of 16O12C18O

Empirical rovibrational energy levels are presented for the third most abundant, asymmetric carbon dioxide isotopologue, 16O12C18O, based on a compiled dataset of experimental rovibrational transitions collected from the literature. The 52 literature sources utilized provide 19,438 measured lines with unique assignments in the wavenumber range of 2-12,676 cm-1. The MARVEL (Measured Active Rotational-Vibrational Energy Levels) protocol, which is built upon the theory of spectroscopic networks, validates the great majority of these transitions and outputs 8786 empirical rovibrational energy levels with an uncertainty estimation based on the experimental uncertainties of the transitions. Issues found in the literature data, such as misassignment of quantum numbers, typographical errors, and misidentifications, are fixed before including them in the final MARVEL dataset and analysis. Comparison of the empirical energy-level data of this study with those in the line lists CDSD-2019 and Ames-2021 shows good overall agreement, significantly better for CDSD-2019; some issues raised by these comparisons are discussed

MARVEL Analysis of the Measured High-Resolution Rovibronic Spectra of 90Zr16O

Zirconium oxide(ZrO) is an important astrophysical molecule that defines the S-star classification class for cool giant stars. Accurate, empirical rovibronic energy levels, with associated labels and uncertainties, are reported for 9 low-lying electronic states of the diatomic 90Zr16O molecule. These 8088 empirical energy levels are determined using the Marvel (Measured Active Rotational-Vibrational Energy Levels) algorithm with 23 317 input assigned transition frequencies, 22 549 of which were validated. A temperature-dependent partition function is presented alongside updated spectroscopic constants for the 9 low-lying electronic states

The W2020 Database of Validated Rovibrational Experimental Transitions and Empirical Energy Levels of Water Isotopologues. II. H₂¹⁷O and H₂¹⁸O with an Update to H₂¹⁶O

The W2020 database of validated experimental transitions and accurate empirical energy levels of water isotopologues, introduced in the work of Furtenbacher et al. [J. Phys. Chem. Ref. Data 49, 033101 (2020)], is updated for H216O and newly populated with data for H217O and H218O. The H217O/H218O spectroscopic data utilized in this study are collected from 65/87 sources, with the sources arranged into 76/99 segments, and the data in these segments yield 27 045/66 166 (mostly measured) rovibrational transitions and 5278/6865 empirical energy levels with appropriate uncertainties. Treatment and validation of the collated transitions of H216O, H217O, and H218O utilized the latest, XML-based version of the MARVEL (Measured Active Rotational-Vibrational Energy Levels) protocol and code, called xMARVEL. The empirical rovibrational energy levels of H217O and H218O form a complete set through 3204 cm-1 and 4031 cm-1, respectively. Vibrational band origins are reported for 37 and 52 states of H217O and H218O, respectively. The spectroscopic data of this study extend and improve the data collated by an International Union of Pure and Applied Chemistry Task Group in 2010 [J. Tennyson et al., J. Quant. Spectrosc. Radiat. Transfer 110, 2160 (2010)] as well as those reported in the HITRAN2016 information system. Following a minor but significant update to the W2020-H216O dataset, the joint analysis of the rovibrational levels for the series H216O, H217O, and H218O facilitated development of a consistent set of labels among these three water isotopologues and the provision of accurate predictions of yet to be observed energy levels for the minor isotopologues using the combination of xMARVEL results and accurate variational nuclear-motion calculations. To this end, 9925/8409 pseudo-experimental levels have been derived for H217O/H218O, significantly improving the coverage of accurate lines for these two minor water isotopologues up to the visible region. The W2020 database now contains almost all of the transitions, apart from those of HD16O, required for a successful spectroscopic modeling of atmospheric water vapor