Term Values Research Articles

Thermal Variability in the Lublin Region During the Frost Wave in January 2017

<p>Fale mrozów należą do ekstremalnych zjawisk pogodowych stanowiących – podobnie jak inne tego typu zjawiska – zagrożenie dla zdrowia i życia człowieka oraz wpływających niekorzystnie na środowisko przyrodnicze. Za falę mrozów przyjmuje się ciąg przynajmniej trzech kolejnych dni, podczas których minimalna dobowa temperatura powietrza była równa lub niższa od –15°C (Wibig i in. 2009). Celem niniejszej pracy jest zbadanie warunków termicznych na Lubelszczyźnie podczas szczególnie mroźnego stycznia 2017 r. Jako materiał źródłowy wykorzystano wyniki pomiarów minimalnych i maksymalnych dobowych wartości temperatury powietrza oraz terminowe wartości temperatury powietrza o kroku czasowym 1 godziny, z terenowych stacji meteorologicznych Katedry Hydrologii i Klimatologii UMCS, zlokalizowanych na obszarze Lubelszczyzny (Celejów, Leśniowice, Rybczewice, Wola Wereszczyńska, Guciów) oraz stacji meteorologicznych IMGW-PIB (Siedlce, Terespol, Lublin-Radawiec, Włodawa, Sandomierz, Zamość, Kozienice). Fala mrozów na Lubelszczyźnie wystąpiła w dniach od 5 do 11 stycznia 2017 r., przy czym na większości stacji (z wyjątkiem stacji w Terespolu) 9 stycznia minimalna dobowa temperatura powietrza była wyższa od –15°C. Podczas analizowanego okresu najniższą temperaturę powietrza zanotowano 7 stycznia na stacji w Guciowie (–25,3°C). Przyczyną tej fali mrozów był napływ powietrza arktycznego z północy.</p>

Fourier-transform spectroscopy, relativistic electronic structure calculation, and coupled-channel deperturbation analysis of the fully mixed A1Σu+ and b3Πu states of Cs2

The 4503 rovibronic term values belonging to the mutually perturbed $A^1\Sigma^+_u$ and $b^3\Pi_u$ states of Cs$_2$ were extracted from laser induced fluorescence (LIF) $A\sim b\rightarrow X^1\Sigma^+_g$ Fourier transform spectra with the 0.01 cm$^{-1}$ uncertainty. The experimental term values of the $A^1\Sigma^+_u\sim b^3\Pi_u$ complex covering the rotational levels $J\in [4,395]$ in the excitation energy range $[9655,13630]$ cm$^{-1}$ were involved into coupled-channel (CC) deperturbation analysis. The deperturbation model takes explicitly into account spin-orbit coupling of the $A^1\Sigma^+_u(A0^+_u)$ and $b^3\Pi^+_{0_u}(b0^+_u)$ states as well as spin-rotational interaction between the $\Omega=0$, $1$ and $2$ components of the $b^3\Pi^+_{\Omega_u}$ state. The \emph{ab initio} relativistic calculations on the low-lying electronic states of Cs$_2$ were accomplished in the framework of Fock space relativistic coupled cluster (FSRCC) approach to provide the interatomic potentials of the interacting $A0^+_u$ and $b0^+_u$ states as well as the relevant $A\sim b$ spin-orbit coupling function. To validate the present CC deperturbation analysis solely obtained by energy-based data, the $A\sim b \to X(v^{\prime\prime}_X)$ LIF intensity distributions were measured and compared with their theoretical counterparts obtained by means of the non-adiabatic vibrational wave functions of the $A\sim b$ complex and the FSRCC $A\sim b \to X$ transition dipole moments calculated by the finite-field method.

PFI-ZEKE-photoelectron spectroscopy of N2O using narrow-band VUV laser radiation generated by four-wave mixing in Ar using a KBBF crystal.

A new nonlinear optical scheme relying on sum-frequency mixing in a KBe2BO3F2 crystal has been used to generate intense, broadly tunable, narrow-bandwidth, coherent vacuum-ultraviolet (VUV) radiation beyond 16 eV by resonance-enhanced four-wave mixing in Ar. The VUV radiation was used to record high-resolution pulsed-field-ionization zero-kinetic-energy photoelectron spectra of the N2O+ A+ ← N2O X photoionizing transition in the wave-number range from 132 000 cm-1 to 135 000 cm-1. The rotational structure of almost all vibrational levels of the A+ state with vibrational term values up to 2700 cm-1 could be resolved, and improved values of the first two adiabatic ionization energies of N2O, corresponding to the formation of the X+ 2Π3/2(000) J+ = 3/2 and A+ 2Σ+(000) N+ = 0 levels of N2O+ from the X 1Σ+(000) J″ = 0 ground state [103 969.30(12) cm-1 and 132 197.70(12) cm-1, respectively], were derived. The rotational intensity distributions of the bands were found to depend strongly on the value of the vibrational angular momentum of the ionic levels. The vibrational structure is discussed in terms of previously reported effective-Hamiltonian analyses.

The spin-orbit coupling of the [formula omitted] and 43Π states in KCs: Observation and deperturbation

Energies of 1655 rovibrational levels of the mutually perturbed 61Σ+ and 43Π0+ states in KCs were measured in a series of experiments employing polarization labelling spectroscopy technique. The experimental term values of the 61Σ+∼43Π0+ complex in KCs were used in coupled-channels deperturbation analysis which took explicitly into account the spin-orbit coupling of the 61Σ+ and 43Π0+ states. The empirical deperturbation treatment was supported by ab initio electronic structure calculation of adiabatic potentials of the interacting states and of the corresponding spin-orbit coupling matrix element as a function of internuclear distance.

Non-adiabatic mass correction for excited states of molecular hydrogen: Improvement for the outer-well HH¯ 1Σg + term values.

The mass-correction function is evaluated for selected excited states of the hydrogen molecule within a single-state nonadiabatic treatment. Its qualitative features are studied at the avoided crossing of the EF with the GK state and also for the outer well of the HH¯ state. For the HH¯ state, a negative mass correction is obtained for the vibrational motion near the outer minimum, which accounts for most of the deviation between experiment and earlier theoretical work.

Theoretical analysis of 4f25d2 configuration of singly ionized praseodymium

Praseodymium (Pr) belongs to Lanthanide group; it has an unfilled f shell. Atomic Praseodymium is very rich in fine levels. Atomic structures both Pr I and Pr II have still not been completely classified. Few researchers have studied Pr fine structures theoretically. The 4f25d2 configuration of singly ionized Praseodymium (Pr II) has been investigated and term values, fine levels angular momenta and coupled wave functions arising from this configuration are being reported in this paper. To calculate the term values and wave functions, Russell-Saunders (L-S) and coefficient of fractional parentage methods have been used respectively. Spectroscopic terms for 4f25d2 configuration are 187, 457 J values of possible fine levels and 106 wave functions of given configuration have also been found. Wavefunctions could be used to calculate the energies of terms, transition probabilities, etc.

Uninsured by Choice? A choice experiment on long term care insurance

We examine evidence from two unique discrete choice experiments (DCE) on long term care insurance and values several of its relevant attributes. More specifically, the experiments examine choices made by a large sample made of 15,298 individuals in the United States with and without insurance. We study the valuation of a number of insurance attributes, namely the daily insurance benefit, insurance coverage, the compulsory and voluntary nature of the insurance policy design, alongside the costs (insurance premium) and health requirements. This paper elicits both respondents’ preferences and willingness to pay (WTP) for these care insurance's attributes using a random parameter logit model, and assesses the heterogeneity of choice responses using demographic, socioeconomic and attitudinal motivations to segment response to insurance choices. We find that an increase in the insurance premium by an additional $100 would reduce insurance uptake by 1pp. Insurance policy uptake is higher when it provides benefits for the lifetime (the monthly marginal WTP being $178.64), and voluntary (the monthly marginal WTP increases by an extra $74.71) as opposed to universal, and when it forgoes health checks (the monthly marginal WTP increases by an extra 28US$).

Word sense disambiguation using semantic kernels with class-based term values

Word sense disambiguation using semantic kernels with class-based term values

Fourier-transform spectroscopy of the A2Πi − X2Σ+ system in CO+ and deperturbation analysis of the A2Πi(v = 0, 1) levels

The A2Πi state of 12C16O+ has been reinvestigated using high-resolution, emission spectra obtained via Fourier-transform spectroscopy of the (0, 1), (0, 2), (1, 0) and (1, 1) bands of the Comet–Tail (A2Πi − X2Σ+) system with accuracy of up to 0.005 cm−1. The high temperature (900 K) of the emission discharge inside the hollow-cathode lamp permitted monitoring of high rotational quantum levels in A2Πi(v = 0, 1) up to J = 48.5. All these bands together with the X2Σ+ − X2Σ+(10, 1) and (10, 2) transitions deriving from a complex, spin-orbit, spin-electronic and L-uncoupling A2Π(v = 0) ∼ X2Σ+(v = 10) interaction as well as the B2Σ+ − X2Σ+(6, 10) frequency transitions from our previous study were taken into consideration. In total, 1849 spectral lines were included in the comprehensive deperturbation analysis. This fit leads to a much improved description in terms of deperturbed molecular constants and interaction parameters compared to the previous studies of the same energy region in CO+. Moreover, the ro-vibronic term values of the A2Πi(v = 0) level and its perturber X2Σ+(v = 10) were determined as well as Λ-doubling of A2Πi(v = 0,1), γ-doubling of X2Σ+(v = 10) and percentage 2Π character of these levels were considered in detail.

Purpose in life and conflict-related neural responses during health decision-making.

Having a strong sense of purpose in life is associated with positive health behaviors. However, the processes through which purpose leads to health are unclear. The current study compared neural activity among individuals with higher versus lower purpose while they made health-related decisions in response to messages promoting health behavior change. A total of 220 adults with a sedentary lifestyle who were likely to feel conflicted in response to health messages underwent functional MRI while viewing messages encouraging physical activity and indicated the self-relevance of the messages. We focused on activity within dorsal anterior cingulate cortex (dACC), anterior insula (AI), dorsolateral prefrontal cortex (DLPFC), and ventrolateral prefrontal cortex (VLPFC) as identified by meta-analytically defined maps of regions previously implicated in conflict-related processing, while participants considered the self-relevance of the messages. Individuals with higher (vs. lower) purpose showed less activity in dACC, AI, DLPFC, and VLPFC while making health-decisions. Lower brain response in these regions mediated the effect of higher purpose on greater endorsement of the messages. Individuals with strong purpose may be less likely to experience conflict-related regulatory burden during health decision-making, which may in turn allow them to accept conflicting yet beneficial health messages. Reduced brain reactivity in dACC, AI, DLPFC, and VLPFC may reflect reduced conflict-related processing during health decision-making relevant to longer term lifestyle goals. This adds to mounting evidence linking purpose and a range of positive health-related outcomes, as well as evidence suggesting that dACC, AI, DLPFC, and VLPFC track conflict-related processes relevant to longer term goals and values. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Experimental study of the 61Σg+ state of the rubidium dimer

This paper reports a high-resolution experimental study and a numerical analysis of the ${\mathrm{Rb}}_{2}\phantom{\rule{4pt}{0ex}}{6}^{1}{\mathrm{\ensuremath{\Sigma}}}_{g}^{+}$ ion-pair state. A large number of rovibrational term values spanning a wide range of the rotational and vibrational quantum numbers were measured using the optical-optical double-resonance technique. The set of term values was simulated with a model of a piecewise multiparameter potential-energy function based on the generalized splines. This function reproduces the experimental data with reasonable accuracy and, in addition, allows us to incorporate in the potential function the nontrivial features at longer internuclear range, such as multiple wells, predicted by the ab initio calculations.

An accurate semi-empirical potential model for the a 3Σu + state of the alkali dimers Na2, K2, Rb2, and Cs2 which reproduces the scattering length.

A new four parameter Tang-Toennies type potential model is described for the a 3Σu + triplet state of the alkali dimers Na2, K2, Rb2, and Cs2. Compared to an earlier three parameter semi-empirical model based on the experimental well depth, De, well location, Re, and the harmonic vibrational frequency, ωe [Lau et al., J. Chem. Phys. 145, 194308 (2016)], the new model is also adjusted to be consistent with the scattering length. The results are shown to have a similar good agreement with the spectroscopic term values as the earlier model with the advantage that the scattering length is properly described. The deviations from recent potentials for Cs2 are discussed.

Anomalous Intensities in the 2+1 REMPI Spectrum of the E 1Π-X 1Σ+ Transition of CO.

We report on one-color experiments near 214 nm involving the photodissociation of jet-cooled OCS to produce high rotational states (40 < J < 80) of CO (X 1Σ+, v = 0, 1) which were then ionized by 2+1 resonance-enhanced multiphoton ionization via the E 1Π state. The nominally forbidden Q-branch of the two-photon E 1Π-X 1Σ+ transition is observed with intensity comparable to the allowed R-branch. The bright character of the high- J Q-branch lines can be described quantitatively as intensity borrowing due to mixing of the E 1Π and C 1Σ+ states, using J-dependent mixing coefficients extrapolated from the observed Λ-doubling in the lower rotational levels of the E state. In addition to the significant enhancement of Q-branch intensities above the values predicted by conventional two-photon line strengths for a 1Π-1Σ+ transition, the high- J lines of the R- and P-branches appear to be suppressed in intensity by approximately a factor of 3 compared to the unperturbed low- J line strengths, most likely due to perturbations associated with a 1Σ- state. The E-state rotational term values for J < 80, v = 0 derived from the present spectra agree within our measurement and calibration uncertainties with the extrapolations based on the molecular constants previously derived from rotational levels with J < 50. The E-X transition is attractive for future application to photodissociation dynamics and rotational polarization measurements of CO photofragments, with convenient access to state-selective probing on multiple rotational branches, which exhibit different sensitivity to fragment alignment.

MDFF Error Analysis: A Tool for Determining Stereochemical and Thermodynamic Correct Structures

Popular methods such as molecular Dynamics Flexible Fitting (MDFF), xMDFF for low resolution X-ray Crystallography and very recently developed resolution exchange, ReMDFF, provide a precise tool to fit atomic structures of a protein inside an electron density map to improve the resolution of the protein structure. Typically, MDFF incorporates the electron microscopy (EM) data as an external potential (UEM) added to the standard molecular dynamics force field, such that the high-density areas in the map correspond to energy minima, where the atoms are subject to forces proportional to the gradient of the EM map. However, the error involved in biasing the standard potential with UEM has not been explored yet. Re-casting UEM in an integro-differential form, reveals a hidden error energy term reminiscent of long-range interactions between stationary masses. This additional contribution to the force filed unnecessarily contorts the molecular geometries during an MDFF refinement. We perform, a quantitative assessment of the effect of this hidden error term in MDFF's grid force field using recently published structures using EM to Protein Data Bank, of varying residues, 200 - 20,000 with 3-8 Å resolution and their corresponding electron density maps. The initial systems are prepared using default MDFF settings, for different grid force scaling parameter. The protein structure files are modified by replacing the charge with atoms mass multiplied by a factor proportional to the error term. The mass-based coulomb like potential is then calculated using NAMD Energy where the structures corresponding to low and high error term values are used and run through MolProbity for comparison of their relative stabilities. Our results indicate, re-weighting an ensemble of structures based on the error-energy term, provides improvement in determining both stereochemical and thermodynamic correct structures of proteins from electron density maps.

Application of the coupled-cluster CC(P;Q) approaches to the magnesium dimer

ABSTRACTSeveral coupled-cluster approaches with an approximate treatment of connected triply or quadruply excited clusters, including the CCSD(T), , and CR-CC(2,3) corrections to CCSD, the active-space CCSDt and CCSDTq methods, and the CC(t;3) and CC(q;4) corrections to CCSDt and CCSDTq derived using the CC(P;Q) framework, and their CCSDT and CCSDTQ parents are applied to the ground-state potential curve and vibrational term values of the magnesium dimer. The correlation-consistent aug-cc-pV(n+d)Z and aug-cc-pwCVnZ ( and Q) basis sets are used. Among the noniterative triples corrections to CCSD, the CR-CC(2,3) approach performs the best, but, in analogy to the previously studied beryllium dimer [I. Magoulas et al., J. Phys. Chem. A 122, 1350 (2018)], the CC(t;3) and CC(q;4) methods outperform other employed approaches in reproducing the CCSDT and CCSDTQ data. Composite calculations combining the nearly all-electron CCSDT and valence CC(q;4) and CCSDTQ computations reproduce the experimentally resolved part of the vibrational spectrum of to within ∼1 when the vibrational spacings are examined, while predicting five extra vibrational states near the dissociation threshold, which have not been experimentally resolved. The corresponding binding energies and equilibrium bond lengths are within a few and 0.01 Å from their experimentally derived values.

Fourier-transform spectroscopy, direct potential fit, and electronic structure calculations on the entirely perturbed (4)1Πstate of RbCs

We perform a high-resolution Fourier-transform spectroscopic study of the $(4){\phantom{\rule{0.16em}{0ex}}}^{1}\mathrm{\ensuremath{\Pi}}$ state of the RbCs molecule by applying two-step $(4){\phantom{\rule{0.16em}{0ex}}}^{1}\mathrm{\ensuremath{\Pi}}\ensuremath{\leftarrow}A{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Sigma}}}^{+}\ensuremath{\sim}b{\phantom{\rule{0.16em}{0ex}}}^{3}\mathrm{\ensuremath{\Pi}}\ensuremath{\leftarrow}X{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Sigma}}}^{+}$ optical excitation followed by observation of the $(4){\phantom{\rule{0.16em}{0ex}}}^{1}\mathrm{\ensuremath{\Pi}}\ensuremath{\rightarrow}X{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Sigma}}}^{+}$ laser-induced fluorescence (LIF) spectra. In many LIF progressions the collision-induced satellite rotational lines are observed, thus increasing the amount of term values and allowing us to estimate the $\mathrm{\ensuremath{\Lambda}}$-doubling effect in the $(4){\phantom{\rule{0.16em}{0ex}}}^{1}\mathrm{\ensuremath{\Pi}}$ state. The direct potential fit (DPF) of experimental term values of 777 rovibronic levels of both $^{85}\mathrm{RbCs}$ and $^{87}\mathrm{RbCs}$ isotopologues is performed by means of the robust weighted nonlinear least-squares method. The DPF analysis based on the adiabatic approximation and analytical expanded Morse oscillator potential reveals numerous regular shifts in the measured level positions. The spectroscopic studies of the $(4){\phantom{\rule{0.16em}{0ex}}}^{1}\mathrm{\ensuremath{\Pi}}$ state are supported by the electronic structure calculations including the potential energy curves of the singlet- and triplet-state manifold and spin-allowed transition dipole moments. The subsequent estimates of radiative lifetimes and corresponding vibronic branching ratios elucidate a dominant contribution of the $(4){\phantom{\rule{0.16em}{0ex}}}^{1}\mathrm{\ensuremath{\Pi}}\ensuremath{\rightarrow}A\ensuremath{\sim}b$ channel into the total radiative decay of the $(4){\phantom{\rule{0.16em}{0ex}}}^{1}\mathrm{\ensuremath{\Pi}}$ state. The relative intensity distributions simulated for $(4){\phantom{\rule{0.16em}{0ex}}}^{1}\mathrm{\ensuremath{\Pi}}\ensuremath{\rightarrow}X{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Sigma}}}^{+}$ LIF progressions agree well with their observed counterparts even for the profoundly shifted levels of the entirely perturbed $(4){\phantom{\rule{0.16em}{0ex}}}^{1}\mathrm{\ensuremath{\Pi}}$ state. To get insight into the origin of the intramolecular perturbations, the relevant spin-orbit- and $L$-uncoupling electronic matrix elements are evaluated.

The Rb2 31Π g state: Observation and analysis.

This paper reports observations and analysis of the Rb2 31Π g state. A total of 323 rovibrational term values spanning the range of the rotational quantum number J = 7 through 77 and the vibrational quantum number = 2 through 23 (about 1/3 of the potential well depth) were measured using the optical-optical double resonance technique. The term values are simulated within a model of a piece-wise multi-parameter potential energy function based on the generalized splines. This function not only enables a reproduction of the experimental data with a reasonable quality but also approximates the available ab initio function in its whole range with a uniform accuracy.

Fundamental vibration frequency and rotational structure of the first excited vibrational level of the molecular helium ion ( ).

The term values of the rotational levels of the first excited vibrational state of the electronic ground state of with a rotational quantum number N + ≤ 13 have been determined with an accuracy of 1.2 × 10-3 cm-1 (∼35 MHz) by multichannel-quantum-defect-theory-assisted Rydberg spectroscopy of metastable He2. Comparison of the experimental term values with the most accurate ab initio results for available in the literature [W.-C. Tung, M. Pavanello, and L. Adamowicz, J. Chem. Phys. 136, 104309 (2012)] reveals inconsistencies between the theoretical and experimental results that increase with increasing rotational quantum numbers. The fundamental vibrational wavenumber of was determined to be 1628.3832(12) cm-1 by fitting effective molecular constants to the obtained term values.

Fourier transform emission spectroscopy and ab initio calculations on the visible spectrum of AlD[formula omitted

The spectrum of the AlD+ isotopologue has been investigated at high resolution in the 27,000−29,000 cm−1 region using a Fourier transform emission spectroscopy technique. The AlD+ molecules were produced within a water-cooled aluminum hollow-cathode lamp in the presence of 1.5 Torr of Ne and 0.8 Torr of ND3. The (0, 0) and (1, 1) bands belonging to the A2Π−X2Σ+system were recorded with an instrumental resolution of 0.03 cm−1. In total, almost 500 rotational frequencies were measured with an absolute accuracy of about 0.005 cm−1. It improved the experimental accuracy of the determined frequencies by the factor 10 compared to the previous work [J Phys B: Mol Phys 1984;17:L861-L866]. The rotational analysis has shown irregularities in the Λ− doubling splitting of the A2Π v=0,1. Consequently, the A2Π state has been represented by the rotational term values, while the regular X2Σ+ state by the molecular constants. The causes of the irregularities were identified in the interaction between the A2Π and the B2Σ+ states, which lies about 3720 cm−1 above. Supporting ab initio quantum chemical calculations, including spin-orbit effects, reproduce the observed spectroscopic constants including the small energy splittings due to spin-rotation interactions (for 2Σ+ states) and Λ−doubling.

Far-infrared synchrotron-based spectroscopy of CH3SH from 50 to 560 cm−1: Near-free-rotor torsion-rotation structure and torsion-vibration interactions

Analysis of torsion-rotation structure in the far-infrared Fourier transform synchrotron spectrum of CH332SH recorded from 50 to 560 cm−1 at the Far-Infrared Beamline of the Canadian Light Source has been extended to higher near-free rotor torsional states reaching up into the region of the small-amplitude vibrations. A variety of sub-bands has been assigned for torsional quantum number up to vt = 5, expanding the database of ground-state energy term values to higher K and vt levels to provide a broad foundation for associated investigations of the vibrational spectrum. The origins of the high-vt sub-states fit quite well to a pattern of free-rotor parabolic curves as a function of K, but with a lower value of the torsional constant F than obtained from previous global analysis of lower-vt data. Numerous resonances perturbing and mixing coupled near-degenerate sub-states have been observed, arising from interactions both within the ground state and between ground and excited vibrational levels.