Functional response and predation rate of Cryptolaemus montrouzieri (Coleoptera: Coccinellidae) to Paracoccus marginatus (Hemiptera: Pseudococcidae) at different temperatures.

The ladybug, Cryptolaemus montrouzieri (Mulsant) (Coleoptera: Cocccinellidae)(Mulsant)(Coleoptera: Cocccinellidae), is a highly efficient predator in controlling mealybug populations and is considered an effective agent for controlling the papaya mealybugs (Paracoccus marginatus) (Williams & Granara de Willink) (Hemiptera: Pseudococcidae). Various criteria have been proposed for evaluating predator effectiveness, with the consumption rate of prey by individual predators, specifically the functional response, emerging as a common and crucial metric. This study evaluated the functional responses of third- and fourth-instar larvae, as well as male and female adults (<48 h old) of C. montrouzieri to adult females of P. marginatus at 3 different temperatures (22 °C, 28 °C, and 35 °C) with 70% ±â€…5% RH and a 12L:12D h photoperiod. Prey densities were 2, 4, 8, 16, 32, 45, or 60 papaya mealybugs per predator for all tests. The response to prey density by third- and fourth-instar larvae or both sexes of adult C. montrouzieri was a type II at all temperatures. The highest attack rate and lowest handling time were estimated at 28 °C in males and 35 °C in females, respectively. The highest daily prey consumption rate occurred at 35 °C in both the immature and adult stages of C. montrouzieri. These findings support the potential of C. montrouzieri in controlling the papaya mealybug, especially in tropical and subtropical regions, given its search efficiency at high temperatures tested in this study. However, additional field investigations are needed to ascertain the control efficacy of C. montrouzieri for this mealybug in biocontrol programs.

A Combined Manual Annotation and Deep-Learning Natural Language Processing Study on Accurate Entity Extraction in Hereditary Disease Related Biomedical Literature.

We report a combined manual annotation and deep-learning natural language processing study to make accurate entity extraction in hereditary disease related biomedical literature. A total of 400 full articles were manually annotated based on published guidelines by experienced genetic interpreters at Beijing Genomics Institute (BGI). The performance of our manual annotations was assessed by comparing our re-annotated results with those publicly available. The overall Jaccard index was calculated to be 0.866 for the four entity types-gene, variant, disease and species. Both a BERT-based large name entity recognition (NER) model and a DistilBERT-based simplified NER model were trained, validated and tested, respectively. Due to the limited manually annotated corpus, Such NER models were fine-tuned with two phases. The F1-scores of BERT-based NER for gene, variant, disease and species are 97.28%, 93.52%, 92.54% and 95.76%, respectively, while those of DistilBERT-based NER are 95.14%, 86.26%, 91.37% and 89.92%, respectively. Most importantly, the entity type of variant has been extracted by a large language model for the first time and a comparable F1-score with the state-of-the-art variant extraction model tmVar has been achieved.

Water diffusion measurements of single charged aerosols using H2O/D2O isotope exchange and Raman spectroscopy in an electrodynamic balance.

Sea spray aerosols contain a large array of organic compounds that contribute to high viscosities at low relative humidity and temperature thereby slowing translational diffusion of water. The Stokes-Einstein equation describes how viscosity is inversely correlated with the translational diffusion coefficient of the diffusing species. However, recent studies indicate that the Stokes-Einstein equation breaks down at high viscosities achieved in the particle phase (>1012 Pa s), underestimating the predicted water diffusion coefficient by orders of magnitude and revealing the need for directly studying the diffusion of water in single aerosols. A new method is reported for measuring the water diffusion coefficient in single suspended charged sucrose-water and citric acid (CA)-water microdroplets in the 30-60 micron diameter range. The translational water diffusion coefficient is quantified using the H2O/D2O isotope exchange technique between 26 and 54% relative humidity (RH) for sucrose and 7 and 25% RH for CA using a recently developed mobile electrodynamic balance apparatus. The results are in good agreement with the literature, particularly the Vignes-type parameterization from experiments using isotope exchange and optical tweezers. Below 15% RH, CA droplets show incomplete H2O/D2O exchange. This mobile electrodynamic balance will allow future studies of atmospherically relevant chemical systems, including field studies.

Publisher Correction: Probing the nature of gold-carbon bonding in gold-alkynyl complexes.

This corrects the article DOI: 10.1038/ncomms3223.

Conformation-selective resonant photoelectron imaging from dipole-bound states of cold 3-hydroxyphenoxide.

We report a photoelectron imaging and photodetachment study of cryogenically cooled 3-hydroxyphenoxide (3HOP) anions, m-HO(C6H4)O-. In a previous preliminary study, two conformations of the cold 3HOP anions with different dipole bound states were observed [D. L. Huang et al., J. Phys. Chem. Lett. 6, 2153 (2015)]. Five near-threshold vibrational resonances were revealed in the photodetachment spectrum from the dipole-bound excited states of the two conformations. Here, we report a more extensive investigation of the two conformers with observation of thirty above-threshold vibrational resonances in a wide spectral range between 18 850 and 19 920 cm-1 (∼1000 cm-1 above the detachment thresholds). By tuning the detachment laser to the vibrational resonances in the photodetachment spectrum, high-resolution conformation-selective resonant photoelectron images are obtained. Using information of the autodetachment channels and theoretical vibrational frequencies, we are able to assign the resonant peaks in the photodetachment spectrum: seventeen are assigned to vibrational levels of anti-3HOP, eight to syn-3HOP, and five to overlapping vibrational levels of both conformers. From the photodetachment spectrum and the conformation-selective resonant photoelectron spectra, we have obtained fourteen fundamental vibrational frequencies for the neutral syn- and anti-m-HO(C6H4)O⋅ radicals. The possibility to produce conformation-selected neutral beams using resonant photodetachment via dipole-bound excited states of anions is discussed.

Time-resolved photoelectron spectroscopy of a dinuclear Pt(II) complex: Tunneling autodetachment from both singlet and triplet excited states of a molecular dianion.

Time-resolved pump-probe photoelectron spectroscopy has been used to study the relaxation dynamics of gaseous [Pt2(µ-P2O5H2)4 + 2H](2-) after population of its first singlet excited state by 388 nm femtosecond laser irradiation. In contrast to the fluorescence and phosphorescence observed in condensed phase, a significant fraction of the photoexcited isolated dianions decays by electron loss to form the corresponding monoanions. Our transient photoelectron data reveal an ultrafast decay of the initially excited singlet (1)A2u state and concomitant rise in population of the triplet (3)A2u state, via sub-picosecond intersystem crossing (ISC). We find that both of the electronically excited states are metastably bound behind a repulsive Coulomb barrier and can decay via delayed autodetachment to yield electrons with characteristic kinetic energies. While excited state tunneling detachment (ESETD) from the singlet (1)A2u state takes only a few picoseconds, ESETD from the triplet (3)A2u state is much slower and proceeds on a time scale of hundreds of nanoseconds. The ISC rate in the gas phase is significantly higher than in solution, which can be rationalized in terms of changes to the energy dissipation mechanism in the absence of solvent molecules. [Pt2(µ-P2O5H2)4 + 2H](2-) is the first example of a photoexcited multianion for which ESETD has been observed following ISC.

Bond-bending isomerism of Au2I3-: competition between covalent bonding and aurophilicity.

We report a joint photoelectron spectroscopy and theoretical investigation of the gaseous Au2I3- cluster, which is found to exhibit two types of isomers due to competition between Au-I covalent bonding and Au-Au aurophilic interactions. The covalent bonding favors a bent IAuIAuI- structure with an obtuse Au-I-Au angle (100.7°), while aurophilic interactions pull the two Au atoms much closer, leading to an acutely bent structure (72.0°) with an Au-Au distance of 3.08 Å. The two isomers are separated by a small barrier and are nearly degenerate with the obtuse isomer being slightly more stable. At low temperature, only the obtuse isomer is observed; distinct experimental evidence is observed for the co-existence of a combination of isomers with both acute and obtuse bending angles at room temperature. The two bond-bending isomers of Au2I3- reveal a unique example of one molecule being able to oscillate between different structures as a result of two competing chemical forces.

Conformation-Selective Resonant Photoelectron Spectroscopy via Dipole-Bound States of Cold Anions.

Molecular conformation is important in chemistry and biochemistry. Conformers connected by low energy barriers can only be observed at low temperatures and are difficult to be separated. Here we report a new method to obtain conformation-selective spectroscopic information about dipolar molecular radicals via dipole-bound excited states of the corresponding anions cooled in a cryogenic ion trap. We observed two conformers of cold 3-hydroxyphenoxide anions [m-HO(C6H4)O(-)] in high-resolution photoelectron spectroscopy and measured different electron affinities, 18,850(8) and 18,917(5) cm(-1), for the syn and anti 3-hydroxyphenoxy radicals, respectively. We also observed dipole-bound excited states for m-HO(C6H4)O(-) with different binding energies for the two conformers due to the different dipole moments of the corresponding 3-hydroxyphenoxy radicals. Excitations to selected vibrational levels of the dipole-bound states result in conformation-selective photoelectron spectra. This method should be applicable to conformation-selective spectroscopic studies of any anions with dipolar neutral cores.

Vibrational State-Selective Resonant Two-Photon Photoelectron Spectroscopy of AuS(-) via a Spin-Forbidden Excited State.

Vibrational state-selective resonant two-photon photoelectron spectra have been obtained via a triplet intermediate state ((3)Σ(-)) of AuS(-) near its detachment threshold using high-resolution photoelectron imaging of cryogenically cooled AuS(-) anions. Four vibrational levels of the (3)Σ(-) excited state are observed to be below the detachment threshold. Resonant two-photon absorptions through these levels yield vibrational state-selective photoelectron spectra to the (2)Σ final state of neutral AuS with broad and drastically different Franck-Condon distributions, reflecting the symmetries of the vibrational wave functions of the (3)Σ(-) intermediate state. The (3)Σ(-) excited state is spin-forbidden from the (1)Σ(+) ground state of AuS(-) and is accessed due to strong relativistic effects. The nature of the (3)Σ(-) excited state is confirmed by angular distributions of the photoelectron images and quantum calculations.

Vibrational state-selective autodetachment photoelectron spectroscopy from dipole-bound states of cold 2-hydroxyphenoxide: o-HO(C6H4)O(-).

We report a photodetachment and high-resolution photoelectron imaging study of cold 2-hydroxyphenoxide anion, o - HO(C6H4)O(-), cooled in a cryogenic ion trap. Photodetachment spectroscopy revealed a dipole-bound state (DBS) of the anion, 25 ± 5 cm(-1), below the detachment threshold of 18 784 ± 5 cm−1 (2.3289 ± 0.0006 eV), i.e., the electron affinity of the 2-hydroxyphenoxy radical o - HO(C6H4)O(⋅). Twenty-two vibrational levels of the DBS are observed as resonances in the photodetachment spectrum. By tuning the detachment laser to these DBS vibrational levels, we obtain 22 high-resolution resonant photoelectron spectra, which are highly non-Franck-Condon due to mode-selective autodetachment and the Δv = - 1 propensity rule. Numerous Franck-Condon inactive vibrational modes are observed in the resonant photoelectron spectra, significantly expanding the vibrational information that is available in traditional high-resolution photoelectron spectroscopy. A total of 15 fundamental vibrational frequencies are obtained for the o - HO(C6H4)O(⋅) radical from both the photodetachment spectrum and the resonant photoelectron spectra, including six symmetry-forbidden out-of-plane modes as a result of resonant enhancement.

Photoelectron spectroscopy and theoretical studies of gaseous uranium hexachlorides in different oxidation states: UCl6 (q-) (q = 0-2).

Uranium chlorides are important in actinide chemistry and nuclear industries, but their chemical bonding and many physical and chemical properties are not well understood yet. Here, we report the first experimental observation of two gaseous uranium hexachloride anions, UCl6 (-) and UCl6 (2-), which are probed by photoelectron spectroscopy in conjunction with quantum chemistry calculations. The electron affinity of UCl6 is measured for the first time as +5.3 eV; its second electron affinity is measured to be +0.60 eV from the photoelectron spectra of UCl6 (2-). We observe that the detachment cross sections of the 5f electrons are extremely weak in the visible and UV energy ranges. It is found that the one-electron one-determinental molecular orbital picture and Koopmans' theorem break down for the strongly internally correlated U-5f(2) valence shell of tetravalent U(+4) in UCl6 (2-). The calculated adiabatic and vertical electron detachment energies from ab initio calculations agree well with the experimental observations. Electronic structure and chemical bonding in the uranium hexachloride species UCl6 (2-) to UCl6 are discussed as a function of the oxidation state of U.

Communication: Observation of dipole-bound state and high-resolution photoelectron imaging of cold acetate anions.

We report the observation of a dipole-bound state and a high-resolution photoelectron imaging study of cryogenically cooled acetate anions (CH3COO(-)). Both high-resolution non-resonant and resonant photoelectron spectra via the dipole-bound state of CH3COO(-) are obtained. The binding energy of the dipole-bound state relative to the detachment threshold is determined to be 53 ± 8 cm(-1). The electron affinity of the CH3COO· neutral radical is measured accurately as 26 236 ± 8 cm(-1) (3.2528 ± 0.0010 eV) using high-resolution photoelectron imaging. This accurate electron affinity is validated by observation of autodetachment from two vibrational levels of the dipole-bound state of CH3COO(-). Excitation spectra to the dipole-bound states yield rotational profiles, allowing the rotational temperature of the trapped CH3COO(-) anions to be evaluated.

Probing the vibrational spectroscopy of the deprotonated thymine radical by photodetachment and state-selective autodetachment photoelectron spectroscopy via dipole-bound states.

Deprotonated thymine can exist in two different forms, depending on which of its two N sites is deprotonated: N1[T-H]- or N3[T-H]-. Here we report a photodetachment study of the N1[T-H]- isomer cooled in a cryogenic ion trap and the observation of an excited dipole-bound state. Eighteen vibrational levels of the dipole-bound state are observed, and its vibrational ground state is found to be 238 ± 5 cm-1 below the detachment threshold of N1[T-H]-. The electron affinity of the deprotonated thymine radical (N1[T-H]˙) is measured accurately to be 26 322 ± 5 cm-1 (3.2635 ± 0.0006 eV). By tuning the detachment laser to the sixteen vibrational levels of the dipole-bound state that are above the detachment threshold, highly non-Franck-Condon resonant-enhanced photoelectron spectra are obtained due to state- and mode-selective vibrational autodetachment. Much richer vibrational information is obtained for the deprotonated thymine radical from the photodetachment and resonant-enhanced photoelectron spectroscopy. Eleven fundamental vibrational frequencies in the low-frequency regime are obtained for the N1[T-H]˙ radical, including the two lowest-frequency internal rotational modes of the methyl group at 70 ± 8 cm-1 and 92 ± 5 cm-1.

High-resolution photoelectron imaging of cold C60⁻ anions and accurate determination of the electron affinity of C60.

High-resolution photoelectron imaging and spectroscopy of cold C60⁻ anions are reported using a newly built photoelectron imaging apparatus coupled with an electrospray ionization source and a temperature-controlled cryogenic ion trap. Vibrationally resolved photoelectron spectra are obtained for the detachment transition from the ground state of C60⁻ to that of C60 at various detachment wavelengths from 354.84 nm to 461.35 nm. The electron affinity of C60 is accurately measured to be 2.6835 ± 0.0006 eV. Numerous unexpected vibrational excitations are observed in the photoelectron spectra due to the Jahn-Teller effect in C60⁻ and Hertzberg-Teller vibronic coupling in both C60⁻ and C60. Both the relative intensities of vibrational peaks and their photoelectron angular distributions provide evidence for the vibronic couplings. The observed p-wave-like behavior in the angular distribution of the 00° transition suggests that the electron is detached from an s-type orbital.

Assessment of Quantum Mechanical Methods for Copper and Iron Complexes by Photoelectron Spectroscopy.

Broken-symmetry density functional theory (BS-DFT) calculations are assessed for redox energetics [Cu(SCH3)2]1-/0, [Cu(NCS)2]1-/0, [FeCl4]1-/0, and [Fe(SCH3)4]1-/0 against vertical detachment energies (VDE) from valence photoelectron spectroscopy (PES), as a prelude to studies of metalloprotein analogs. The M06 and B3LYP hybrid functionals give VDE that agree with the PES VDE for the Fe complexes, but both underestimate it by ∼400 meV for the Cu complexes; other hybrid functionals give VDEs that are an increasing function of the amount of Hartree-Fock (HF) exchange and so cannot show good agreement for both Cu and Fe complexes. Range-separated (RS) functionals appear to give a better distribution of HF exchange since the negative HOMO energy is approximately equal to the VDEs but also give VDEs dependent on the amount of HF exchange, sometimes leading to ground states with incorrect electron configurations; the LRC-ωPBEh functional reduced to 10% HF exchange at short-range give somewhat better values for both, although still ∼150 meV too low for the Cu complexes and ∼50 meV too high for the Fe complexes. Overall, the results indicate that while HF exchange compensates for self-interaction error in DFT calculations of both Cu and Fe complexes, too much may lead to more sensitivity to nondynamical correlation in the spin-polarized Fe complexes.

Vibrational spectroscopy of the dehydrogenated uracil radical by autodetachment of dipole-bound excited states of cold anions.

Molecules with large enough dipole moments can bind an electron by the dipole field, which has little effect on the molecular core. A molecular anion can be excited to a dipole-bound state, which can autodetach by vibronic coupling. Autodetachment spectroscopy of a complex anion cooled in a cryogenic ion trap is reported. Vibrational spectroscopy of the dehydrogenated uracil radical is obtained by a dipole-bound state with partial rotational resolution. Fundamental frequencies for 21 vibrational modes of the uracil radical are reported. The electron affinity of the uracil radical is measured accurately to be 3.4810±0.0006 eV and the binding energy of the dipole-bound state is measured to be 146±5 cm(-1). The rotational temperature of the trapped uracil anion is evaluated to be 35 K.

Probing the nature of gold-carbon bonding in gold-alkynyl complexes.

Homogeneous catalysis by gold involves organogold complexes as precatalysts and reaction intermediates. Fundamental knowledge of the gold-carbon bonding is critical to understanding the catalytic mechanisms. However, limited spectroscopic information is available about organogolds that are relevant to gold catalysts. Here we report an investigation of the gold-carbon bonding in gold(I)-alkynyl complexes using photoelectron spectroscopy and theoretical calculations. We find that the gold-carbon bond in the ClAu-CCH(-) complex represents one of the strongest gold-ligand bonds-even stronger than the known gold-carbon multiple bonds, revealing an inverse correlation between bond strength and bond order. The gold-carbon bond in LAuCCH(-) is found to depend on the ancillary ligands and becomes stronger for more electronegative ligands. The strong gold-carbon bond underlies the catalytic aptness of gold complexes for the facile formation of terminal alkynyl-gold intermediates and activation of the carbon-carbon triple bond.

A joint photoelectron spectroscopy and theoretical study on the electronic structure of UCl5- and UCl5.

We report a combined photoelectron spectroscopic and relativistic quantum chemistry study on gaseous UCl5(-) and UCl5. The UCl5(-) anion is produced using electrospray ionization and found to be highly electronically stable with an adiabatic electron binding energy of 4.76±0.03 eV, which also represents the electron affinity of the neutral UCl5 molecule. Theoretical investigations reveal that the ground state of UCl5(-) has an open shell with two unpaired electrons occupying two primarily U 5f(z³) and 5f(xyz) based molecular orbitals. The structures of both UCl5(-) and UCl5 are theoretically optimized and confirmed to have C(4v) symmetry. The computational results are in good agreement with the photoelectron spectra, providing insights into the electronic structures and valence molecular orbitals of UCl5(-) and UCl5. We also performed systematic theoretical studies on all the uranium pentahalide complexes UX5(-) (X=F, Cl, Br, I). Chemical bonding analyses indicate that the U-X interactions in UX5(-) are dominated by ionic bonding, with increasing covalent contributions for the heavier halogen complexes.

Probing the electronic structure and chemical bonding in tricoordinate uranyl complexes UO2X3- (X = F, Cl, Br, I): competition between Coulomb repulsion and U-X bonding.

While uranyl halide complexes [UO2(halogen)n](2-n) (n = 1, 2, 4) are ubiquitous, the tricoordinate species have been relatively unknown until very recently. Here photoelectron spectroscopy and relativistic quantum chemistry are used to investigate the bonding and stability of a series of gaseous tricoordinate uranyl complexes, UO2X3(-) (X = F, Cl, Br, I). Isolated UO2X3(-) ions are produced by electrospray ionization and observed to be highly stable with very large adiabatic electron detachment energies: 6.25, 6.64, 6.27, and 5.60 eV for X = F, Cl, Br, and I, respectively. Theoretical calculations reveal that the frontier molecular orbitals are mainly of uranyl U-O bonding character in UO2F3(-), but they are from the ligand valence np lone pairs in the heavier halogen complexes. Extensive bonding analyses are carried out for UO2X3(-) as well as for the doubly charged tetracoordinate complexes (UO2X4(2-)), showing that the U-X bonds are dominated by ionic interactions with weak covalency. The U-X bond strength decreases down the periodic table from F to I. Coulomb barriers and dissociation energies of UO2X4(2-) → UO2X3(-) + X(-) are calculated, revealing that all gaseous dianions are in fact metastable. The dielectric constant of the environment is shown to be the key in controlling the thermodynamic and kinetic stabilities of the tetracoordinate uranyl complexes via modulation of the ligand-ligand Coulomb repulsions.