Direct dynamics dual-level - -

Dual-level direct dynamics of the hydroxyl radical reaction with ethane and haloethanes Toward a general reaction parameter method ... 

Our third generation direct dynamics scheme is called VTST with interpolated corrections (VTST-IC) or dual-level direct dynamics (DLDD) or triple-slash (///) dynamics. This approach involves three steps [49c] ... 

HL[HessL]///LL denotes a higher level of HL, except for the hessians which are calculated at level HessL, and a lower level of LL in a dual-level direct dynamics calculation. 

A. Femandez-Ramos, J. Rodriguez-Otero and M.A. Rfos, High level and dual level direct dynamics in the intramolecular proton transfer of hydrogenoxalate anion. Influence of tunneling and isotopic effect, J. Phys. Chem. A, 102 (1998) 2954. 

Dual-Level Direct Dynamics Method for Reaction Rate Calculations with Inclusion of Multidimensional Tunneling Effects and Validation for the Reaction of H with trans-N2H2. 

Qualitative analysis is the process of the determination of the presence (or absence) of a particular element or group of elements in a sample. The ability to perform a comprehensive qualitative analysis is directly related to the sensitivity of the analysis method and hence the detection capability. Ideally, it is desirable to determine major, minor, trace, and ultratrace concentration level elements simultaneously on the same sample aliquot, which requires an instrument and technique that exhibits a wide dynamic range of measurement of the ion currents for the various element isotopes. However, in practice, it is often difficult to determine the high intensity of major elements on the same sample dilution as that required for ultratrace concentration element determination (usually measured on undiluted sample). This problem is often accommodated by the use of very low abundance isotopes of the major concentration analyte, reducing the analysis sensitivity. Where no low abundance isotope is available, instrumentation with dual detectors (electron multiplier for low concentration analytes and Faraday analog detectors for high concentration elements) can be used effectively. 

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