Pacific Northwest National Laboratory

About: Pacific Northwest National Laboratory is a facility organization based out in Richland, Washington, United States. It is known for research contribution in the topics: Catalysis & Aerosol. The organization has 11581 authors who have published 27934 publications receiving 1120489 citations. The organization is also known as: PNL & PNNL.

Benchmark calculations with correlated molecular wave functions. I: Multireference configuration interaction calculations for the second row diatomic hydrides

Abstract: Multireference configuration interaction calculations (valence electrons only) based on generalized valence bond (GVB) and complete active space (CAS) self‐consistent field wave functions are used to compute potential energy functions and spectroscopic constants for the second row diatomic hydrides of aluminum through chlorine. The correlation consistent basis sets of Dunning and co‐workers have been used. This suite of sets—standard and augmented sets of double through quintuple zeta quality—provides a systematic means of improving the description of chemical bonding. The regularity of De and re as a function of basis set quality allows extrapolation to an estimated ‘‘complete’’ basis set limit. The error in the CAS+1+2 predictions of De for the five species varies from 0.3 kcal/mol (AlH) to 1.4 kcal/mol (HCl) with a root‐mean‐square (rms) error of 0.7 kcal/mol. The error in re varies from 0.0008 A (SH) to 0.0028 A (SiH) with a rms error of 0.002 A. Other properties are described with comparable accuracy...

Constraining cloud lifetime effects of aerosols using A‐Train satellite observations

Abstract: [1] Aerosol indirect effects have remained the largest uncertainty in estimates of the radiative forcing of past and future climate change Observational constraints on cloud lifetime effects are particularly challenging since it is difficult to separate aerosol effects from meteorological influences Here we use three global climate models, including a multi-scale aerosol-climate model PNNL-MMF, to show that the dependence of the probability of precipitation on aerosol loading, termed the precipitation frequency susceptibility (Spop), is a good measure of the liquid water path response to aerosol perturbation (λ), as both Spop and λ strongly depend on the magnitude of autoconversion, a model representation of precipitation formation via collisions among cloud droplets This provides a method to use satellite observations to constrain cloud lifetime effects in global climate models Spopin marine clouds estimated from CloudSat, MODIS and AMSR-E observations is substantially lower than that from global climate models and suggests a liquid water path increase of less than 5% from doubled cloud condensation nuclei concentrations This implies a substantially smaller impact on shortwave cloud radiative forcing over ocean due to aerosol indirect effects than simulated by current global climate models (a reduction by one-third for one of the conventional aerosol-climate models) Further work is needed to quantify the uncertainties in satellite-derived estimates ofSpop and to examine Spopin high-resolution models

Water-Lean Solvents for Post-Combustion CO2 Capture: Fundamentals, Uncertainties, Opportunities, and Outlook

Abstract: This review is designed to foster the discussion regarding the viability of postcombustion CO2 capture by water-lean solvents, by separating fact from fiction for both skeptics and advocates. We highlight the unique physical and thermodynamic properties of notable water-lean solvents, with a discussion of how such properties could translate to efficiency gains compared to aqueous amines. The scope of this review ranges from the purely fundamental molecular-level processes that govern solvent behavior to bench-scale testing, through process engineering and projections of process performance and cost. Key discussions of higher than expected CO2 mass transfer, water tolerance, and compatibility with current infrastructure are presented along with current limitations and suggested areas where further solvent development is needed. We conclude with an outlook of the status of the field and assess the viability of water-lean solvents for postcombustion CO2 capture.

Disposable Electrochemical Immunosensor Diagnosis Device Based on Nanoparticle Probe and Immunochromatographic Strip

Abstract: We describe a disposable electrochemical immunosensor diagnosis device that integrates the immunochromatographic strip technique with an electrochemical immunoassay and exploits quantum dot (QD, CdS@ZnS) as labels for amplifying signal output. The device takes advantage of the speed and low cost of the conventional immunochromatographic strip test and the high sensitivity of the nanoparticle-based electrochemical immunoassay. A sandwich immunoreaction was performed on the immunochromatographic strip, and the captured QD labels in the test zone were determined by highly sensitive stripping voltammetric measurement of the dissolved metallic component (cadmium) with a disposable screen-printed electrode, which is embedded underneath the membrane on the test zone. The new device coupled with a portable electrochemical analyzer shows great promise for in-field and point-of-care quantitative testing of disease-related protein biomarkers. The parameters (e.g., voltammetric measurement of QD labels, antibody immobilization, the loading amount of QD-antibody, and the immunoreaction time) that govern the sensitivity and reproducibility of the device were optimized with IgG model analyte. The voltammetric response of the optimized device is highly linear over the range of 0.1-10 ng mL(-1) IgG, and the limit of detection is estimated to be 30 pg mL(-1) in association with a 7-min immunoreaction time. The detection limit was improved to 10 pg mL(-1) using a 20-min immunoreaction time. The device has been successfully applied for the detection of prostate-specific antigen (PSA) in human serum sample with a detection limit of 20 pg mL(-1). The results were validated by using the commercial PSA enzyme-linked immunosorbent assay kit and showed high consistency. The new disposable electrochemical diagnosis device thus provides a rapid, clinically accurate, and quantitative tool for protein biomarker detection.

Single molecule emission characteristics in near-field microscopy.

Abstract: In near-field scanning optical microscopy (NSOM), the measured fluorescence lifetime of a single dye molecule can be shortened or lengthened, sensitively dependent on the relative position between the molecule and aluminum coated fiber tip. The modified lifetimes and other emission characteristics are simulated by solving Maxwell equations with the finite-difference time-domain (FDTD) method. The 2D computation reveals insight into the lifetime behaviors and provides guidance for nonperturbative spectroscopic measurements with NSOM. This new methodology is capable of predicting molecular emission properties in front of a metal/dielectric interface of arbitrary geometry.