Formation of Ultracold Heteronuclear Dimers in Electric Fields

The formation of ultracold molecules via stimulated emission followed by a radiative deexcitation cascade in the presence of a static electric field is investigated. By analyzing the corresponding cross sections, we demonstrate the possibility to populate the lowest rotational excitations via photoassociation. The modification of the radiative cascade due to the electric field leads to narrow rotational state distributions in the vibrational ground state. External fields might therefore represent an additional valuable tool towards the ultimate goal of quantum state preparation of molecules

Formation and interactions of cold and ultracold molecules: new challenges for interdisciplinary physics

Progress on researches in the field of molecules at cold and ultracold temperatures is reported in this review. It covers extensively the experimental methods to produce, detect and characterize cold and ultracold molecules including association of ultracold atoms, deceleration by external fields and kinematic cooling. Confinement of molecules in different kinds of traps is also discussed. The basic theoretical issues related to the knowledge of the molecular structure, the atom-molecule and molecule-molecule mutual interactions, and to their possible manipulation and control with external fields, are reviewed. A short discussion on the broad area of applications completes the review.Comment: to appear in Reports on Progress in Physic

Effect of soil storage at 4 °C on the calorespirometric measurements of soil microbial metabolism

Soil samples must usually be stored for a time between collection and measurements of microbial metabolic properties. However, little is known about the influence of storage conditions on microbial metabolism when studied by calorespirometry. Calorespirometry measures the heat rate and the CO2 rate of microbial metabolism, where the ratio of heat and CO2 released, the calorespirometric ratio, informs about the nature of substrates being used by microorganisms. Application to soil microbiology is very recent, and little is known about the influence of the common soil preparation practices between collection and analysis on the calorespirometric measurements. For these reasons, the effect of storage at 4 °C on the microbial metabolism was determined by calorespirometry. Results show CO2 production rate decreases with storage time while the evolution of metabolic heat rate is more stable. The calorespirometric ratio increases with storage time in soil samples with organic matter characterized by lower carbohydrate contribution to the total carbon and higher aromaticity and is unaffected in soil samples with lower carbohydrates in the organic matter and higher aromaticity. Therefore, the calorespirometric ratio values may vary for the same soil sample, such that the soil organic matter properties, as well as the time stored at 4 °C, must be considered in interpreting calorespirometric data on soils.This work was funded by the project of Xunta de Galicia (10PXIB291027PR). 13C CPMAS analysis were done in the NMR services of the University of Santiago de Compostela (RIAIDT). Thermal analysis and calorimetric measurements were performed in the Elemental Analytical Services (RIAIDT) of the University of Santiago de CompostelaS

Enhanced Transmission through Gold Nanohole Arrays Fabricated by Thermal Nanoimprint Lithography for Surface Plasmon Based Biosensors

AbstractWe present the fabrication of gold nanohole arrays using thermal nanoimprint lithography and integration into a microfluidic device for detection of biological analytes. The biosensor makes use of a surface-plasmon mediated effect known as enhanced optical transmission, in which the transmission of light is modulated. The sensitivity achieved with these gold nanohole arrays has been characterized and up-to 300 RIU/nm were obtained varying the array parameters. Detection of protein biomarkers via capture by specific antibodies has been achieved demonstrating the biosensing capabilities of the fabricated devices