Chirality Recognition/transfer/amplification: Rotational Spectroscopic And Chiroptical Spectroscopic Studies

A molecule is chiral if its mirror image cannot be superimposed onto itself. Chirality serves an essential function in life. Our research program centres on understanding mechanisms of chirality recognition/transfer/amplification at the molecular level. To achieve this goal, we apply and develop new spectroscopic tools to characterize structural and dynamical properties of chiral molecules and non-covalent interactions among them in the gas phase, solution, cold rare gas matrices and at liquid-liquid interfaces. We emphasize the connection between the gas phase and condense phase results obtained using high resolution spectroscopy and several chiroptical spectroscopies, respectively. For example, we examined the conformational landscape and chirality recognition in the binary adducts of tetrahydro-2-furoic acid using chirped pulse Fourier transform microwave spectroscopy. The unusual conformational distributions and chirality controlled conformational preferences will be discussed. Using vibrational circular dichroism, we followed the first few steps of self-aggregation of this acid in cold rare gas matrices and compared the results to those obtained in the gas phase and in solution previously. In the second example, I will discuss the unusually strong solvent ‘Raman optical activity’ features observed in a solution of a chiral nickel complex even though the solvent is achiral and the search for its origin. The interplay between experiment and theory is essential for all the work described

Improving Relevance Feedback with Unbiased Estimate of User\u27s Information Need

Relevance feedback is an effective and widely accepted method in information retrieval to improve performance. Relevance feedback generally uses an adaptive learning method to estimate the userís information need. In this research, we propose an alternative two-stage sampling method to obtain an unbiased estimate of the userís information need. Our estimate shows not only improved retrieval performance, but also better prevention of query drift, which troubles traditional relevance feedback. We also give theoretical justification and empirical support for this method

Using Computational Tools To Enhance Learning In An Undergraduate Molecular Spectroscopy Course

In molecular spectroscopy, our models of the molecular world are built on rigorous spectroscopic experimentation and rich interplay between theory and experiment. To instill such appreciation to undergraduate students, who have little experience in either spectroscopic experiments and theory, is challenging. We have developed a new computational laboratory component to complement the material covered in a senior undergraduate course on molecular spectroscopy. Specifically, we focus on illustrating molecular spectroscopic concepts (some of which can be quite abstract and complicated) taught in class with electronic structure calculations. This talk will describe our implementation and the learning outcome. Two particular examples will be discussed. One is related to the misconception that electron density is the main factor responsible for NMR chemical shifts and how we utilize both experimental data and calculations to help students overcome this common misconception. The other deals with differences in geometries, for example, those obtained using rotational constants directly, isotopic substitution procedures, and electronic structure calculations. This talk will also discuss how the above activities worked in practice and the improvements we plan to implement next time

A Concpetual Model of Customer Value in eCommerce

Customer value is crucial in predicting customer choice in traditional consumer behavior research. However, online customer value can be different from its offline counterpart because customer value is highly context-dependent. In online retailing settings, not only the product itself, but also the web store and the Internet channel contribute value to customers. Synthesizing the research in consumer behaviour and IS, we propose an online customer value model with three key components: the outcome value, the process value, and the shopping enjoyment. These three dimensions capture different benefits an online consumer can obtain from a web store. A pilot study with a sample of 89 graduate students was carried out. The preliminary results validate our choice of constructs and test the validity and reliability of the instruments used in this study. With an explicit focus on the customer role of a web user, this value conceptualization is expected to facilitate better understanding of the online consumer behaviour

Studying Users’ Computer Security Behavior Using the Health Belief Model

The increasing frequency of security incidents is a major concern to organizations, and it is therefore important for organizations to protect themselves against security threats. Technological controls are important but not adequate, as the success of security also depends on the effective security behavior of individuals. Information security awareness programs are an important approach but such programs have to be effective in influencing user’s behavior. It is thus important to investigate the factors that will influence a user to practice computer security in the context of an organization. With such motivation in mind, this study uses the Health Belief Model, a well-established model from preventive healthcare, to study users’ computer security behavior. An instrument was developed based on health and security literature and conceptually validated. Data was collected from 134 employees of different organizations and analyzed using multiple regression analysis. Results show that perceived susceptibility, perceived benefits and self-efficacy are determinants of a user’s computer security behavior when applied to exercising care with email attachments. Theoretical and practical implications of this study are discussed

Advertising Effectiveness of Different Social Appeals through Microblog

In today’s interactive marketplace，microblog has become a powerful social marketing and advertising platform. An important type of information in microblog is consumer generated and forwarded advertising. In our study, we explore advertising effects of different social appeals through microblog. We find that oriented appeals (i.e., other-oriented and self-oriented appeals) are more effective than non-oriented appeals. But the difference between other-oriented appeal and self-oriented appeal is insignificant. The relationship between sender and receiver moderate the result. Other-oriented appeal is more effective than self-oriented appeal for dyads with offline relationship, while self-oriented appeal is more effective for dyads of online-only relationship

Infrared and microwave spectra of ne-water complex

The binary complex of rare gas atom and water is an ideal model to study the anisotropic potential energy surface of van der Waals interaction and the large amplitude motion. Although Xe-H$_2$O, Kr-H$_2$O, Ar-H$_2$O, Ar-D$_2$O and even Ne-D$_2$O complexes were studied by microwave or high resolution infrared spectroscopy, the lighter Ne-H$_2$O complex has remained unidentified. In this talk, we will present the theoretical and experimental investigation of the Ne-H$_2$O complex. A four-dimension PES for H$_2$O-Ne which only depended on the intramolecular (Q2) normal-mode coordinate of H2O monomer was calculated in this work to determine the rovibrational energy levels and mid-infrared transitions. Aided with the calculated transitions, we were able to assigned the high resolution mid-infrared spectra of both $^{20}$Ne-H$_2$O and $^{22}$Ne-H$_2$O complexes that are generated with a pulsed supersonic molecular beam in a multipass direct absorption spectrometer equiped with an external cavity quantum cascade laser at 6 $\mu$m. Several bands of both para and ortho Ne-H2O were assigned and fitted using the Hamiltonian with strong Coriolis and angular-radical coupling terms. The predicted groud state energy levels are then confirmed by the J=1-0 and J=2-1 transitions measurement using a cavity based Fourier transform microwave spectrometer