Frozen Rotor Approximation in the Mixed Quantum/Classical Theory for Collisional Energy Transfer: Application to Ozone Stabilization

A frozen-rotor approximation is formulated for the mixed quantum/classical theory of collisional energy transfer and ro-vibrational energy flow [M. Ivanov and D. Babikov, J. Chem. Phys.134, 144107 (Year: 2011)]. Numerical tests are conducted to assess its efficiency and accuracy, compared to the original version of the method, where rotation of the molecule in space is treated explicitly and adiabatically. New approach is considerably faster and helps blocking the artificial ro-vibrational transitions at the pre- and post-collisional stages of the process. Although molecular orientation in space is fixed, the energy exchange between rotational, vibrational, and translational digresses of freedom still occurs, allowing to compute ro-vibrational excitation and quenching. Behavior of the energy transfer function through eight orders of magnitude range of values and in a broad range of ΔE is reproduced well. In the range of moderate −500 ⩽ ΔE ⩽ +500 cm−1 the approximate method is rather accurate. The absolute values of stabilization cross sections for scattering resonances trapped behind the centrifugal threshold are a factor 2-to-3 smaller (compared to the explicit-rotation approach). This performance is acceptable and similar to the well-known sudden-rotation approximation in the time-independent inelastic scattering methods

Improved Potential Energy Surface of Ozone Constructed Using the Fitting by Permutationally Invariant Polynomial Function

New global potential energy surface for the ground electronic state of ozone is constructed at the complete basis set level of the multireference configuration interaction theory. A method of fitting the data points by analytical permutationally invariant polynomial function is adopted. A small set of 500 points is preoptimized using the old surface of ozone. In this procedure the positions of points in the configuration space are chosen such that the RMS deviation of the fit is minimized. New ab initio calculations are carried out at these points and are used to build new surface. Additional points are added to the vicinity of the minimum energy path in order to improve accuracy of the fit, particularly in the region where the surface of ozone exhibits a shallow van der Waals well. New surface can be used to study formation of ozone at thermal energies and its spectroscopy near the dissociation threshold

Quantum mechanical and quasiclassical investigation of the time domain nonadiabatic dynamics of NO2 close to the bottom of the X2A1-A2B2 conical intersection

We use the effective Hamiltonian that we recently fitted against the first 306 experimentally observed vibronic transitions of NO2 [J. Chem. Phys. 119, 5923 (2003)] to investigate the time domain nonadiabatic dynamics of this molecule on the coupled X2A1 and A2B2 electronic states, using both quantum mechanical and quasiclassical techniques. From the quantum mechanical point of view, we show that the transfer of population to the electronic ground state originating from a wave packet launched on the excited state occurs in a stepwise fashion. The evolution of wave packets launched on the electronic ground state is instead more complex because the crossing seam is located close to the bottom of the electronic excited state. We next use the mapping formalism, which replaces the discrete electronic degrees of freedom by continuous ones, to obtain a classical description of the coupled electronic states. We propagate gaussian swarms of trajectories to show that this approach can be used to calculate the populations in each electronic state. We finally propose a very simple trajectory surface hopping model, which assumes that trajectories have a constant probability to jump onto the other state in a particular region of the phase space and a null hopping probability outside from this region. Quasiclassical calculations show that this model enables a precise estimation of complex quantities, like for example the projection of the instantaneous probability density on given planes.Comment: accepted for publication in J. Chem. Phy

Selenoprotein M is expressed during bone development

25 selenoproteins that contain selenium, incorporated as selenocysteine (Sec), have been identified to date. Selenoprotein M (SELM) is one of seven endoplasmic reticulum (ER)-resident, Sec-containing proteins that may be involved in posttranslational processing of proteins and maintenance of ER function. Since SELM was overrepresented in a cartilage- and bone- specific expressed sequence tag (EST) library, we further investigated the expression pattern of Selm and its possible biological function in the skeleton. RNA in situ hybridization of Selm in chicken and mice of different developmental stages revealed prominent expression in bones, specifically in osteoblast, and in tendons. This result suggests that SELM functions during bone development, where it is possibly involved in the processing of secreted proteins

The 16OH/18OH and OD/OH isotope ratios in comet C/2002 T7 (LINEAR)

The 16OH/18OH and OD/OH isotope ratios are measured in the Oort-Cloud comet C/2002 T7 (LINEAR) through ground-based observations of the OH ultraviolet bands at 3063 A (0,0) and 3121 A (1,1) secured with the Very Large Telescope (VLT) feeding the Ultraviolet-Visual Echelle Spectrograph (UVES). From the 16OH/18OH ratio, we find 16O/18O = 425 +/- 55, equal within the uncertainties to the terrestrial value and to the ratio measured in other comets, although marginally smaller. We also estimate OD/OH from which we derive D/H = 2.5 +/- 0.7 10-4 in water. This value is compatible with the water D/H ratios evaluated in other comets and marginally higher than the terrestrial value.Comment: Accepted for publication in A&A Letter

Strategies for successfully engaging all students in live synchronous online classes

A December 2016 study in Psychological Science found that residential students who bring laptops to class frequently use the Internet for nonacademic use, which results in lower class performance. Another study referenced in Fast Company in March 2016 noted that just knowing you have an unread email in your inbox can temporarily lower your IQ by 10 points. How, then, can we discourage students from browsing the Internet or looking at their email when they are attending class on their computer because the course is online? How can we keep their attention focused on the class? At Columbia University’s School of Social Work, we are in our second year of our fully online MSW program. Our courses are taught via weekly live classes hosted in Adobe Connect for 90-120 minutes and led by a course instructor with an associate facilitator and a technical support specialist. In order to engage our students in these classes, instructors use online tools and teaching strategies to make the class sessions interactive. This poster shares active learning tools and strategies for online classrooms. These include creative uses of typed chat, formal & informal polling, webcam, on-screen drawing, live note-taking pods, and breakout rooms. This poster draws from the presenter’s personal experience teaching the fall 2016 online course Macro Community Practice, as well as the following peer-reviewed chapter: Marquart, M., Fleming, M., Rosenthal, S., & Hibbert, M. (2016, March). Instructional Strategies for Synchronous Components of Online Courses. In S. D’Agustino (Ed.), Creating Teacher Immediacy in Online Learning Environments. Hershey, PA: IGI Global. Thank you to the following online instructors for contributing quotes: Mashura Akilova, Johanna Baez, Beth Counselman-Carpenter, Amelia Ortega, John Robertson, and Steven Schinke

The Porter stemming algorithm: then and now

Purpose: In 1980, Porter presented a simple algorithm for stemming English language words. This paper summarises the main features of the algorithm, and highlights its role not just in modern information retrieval research, but also in a range of related subject domains. Design: Review of literature and research involving use of the Porter algorithm. Findings: The algorithm has been widely adopted and extended so that it has become the standard approach to word conflation for information retrieval in a wide range of languages. Value: The 1980 paper in Program by Porter describing his algorithm has been highly cited. This paper provides a context for the original paper as well as an overview of its subsequent use

Overlapping resonances in the control of intramolecular vibrational redistribution

Coherent control of bound state processes via the interfering overlapping resonances scenario [Christopher et al., J. Chem. Phys. 123, 064313 (2006)] is developed to control intramolecular vibrational redistribution (IVR). The approach is applied to the flow of population between bonds in a model of chaotic OCS vibrational dynamics, showing the ability to significantly alter the extent and rate of IVR by varying quantum interference contributions.Comment: 10 pages, 7 figure

Green Modernization – The political, social and societal setting of Morocco’s solar energy policies

In 2009, Morocco initiated an ambitious energy transition program. The aim is to increase the country’s independence from energy imports until 2030. The plan targets the reduction of the import of fossils and large investments into renewable energies. The goal set is to meet 42% of its power generating capacity needs through renewables by 2020 and 52% by 2030. Morocco’s bold and ambitious plans are often highlighted as a model for how to invest into future technologies and bring about clean energy transition. Due to its geography, weather conditions and solar irradiance, Morocco is considered to have huge potentials regarding wind and solar energy production. Morocco’s energy transition program includes the construction of a number of large and medium scale solar plants until 2020. Their planning and construction is often managed by MASEN (Moroccan Agency for Sustainable Energy), a public limited company. Recently, Noor 1, the first of several large scale solar plants was completed. Noor 1 is situated in Ouarzazate in the East of the country. Currently Noor Tata is in the planning phase. Similar with Morocco, energy transition has been also a hot topic in Austria. However, different from Morocco, planning, decision-making and governance structures have rather reflected the country's federal system. Austria's energy transition strategy is a decentralized one. As much as this often entails strong involvement and ownership on societal level, as much its success is dependent on a complex set of diverse political entrepreneurs on different political and administrative levels (national-federal-district and local). LINKS project aims at learning from both; Austrian and Moroccan experiences. In its last phase, the project deals with the question whether decentralized small-scale energy production models as implemented in some of the Austrian energy model regions are transferrable to Morocco. This assessment takes place against the background of the Moroccan state's ambitions to decentralize and strengthen the regional and provincial levels. Accordingly, this report elaborates the structural, political, social and societal setting in which Morocco's energy policy is embedded. The report tries to define the major actors, analyse the decision-making structures, and review the socio-technical imaginaries which have shaped national energy policies. "Socio-technical imaginaries" define mind-sets and frames which do not only guide policies and strategies but also give insights about the expectations connected with technological developments. The report aims at providing a background for the preparation of the stakeholder forum to be held in Tata/Morocco in October 2017. The forum aims at bringing together local and regional stakeholders and to debate at eye level experiences, expectations and ideas for solar energy production in their region. This working paper was produced within the LINKS project (Linking climate change mitigation, energy security and regional development in climate and energy model regions in Austria) (funded by the ACRP)