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This study highlights areas of importance for psychological well-being in the pandemic era, aiming to explain how participants psychological well-being can be enhanced through traditional festival events, and further analyzes the impact of the antecedents of psychological well-being. Data were collected from the racers in the 2021 Macau International Dragon Boat Race using online panels (n = 356). Four alternative models were evaluated using confirmatory factor analysis and structural equation modeling (SEM). The results indicate that the restorative quality of a traditional festival is the crucial predictor of psychological well-being, and within the structures of social exchange theory and cognitive appraisal theory, emotional healing and satisfaction are also important components of an individuals' psychological well-being. The results contribute to the design, organization and management of traditional festival events and this will help organizers to improve participants’ psychological well-being and their relationships during a pandemic.

AbstractThis study investigates the decision-making process for outdoor leisure activities of the Chinese people in the context of COVID-19. An online survey of residents of Heilongjiang Province was conducted in September and October 2020. In total, 441 questionnaires were returned for empirical analysis. The results reveal that fears of contamination and compulsory checking/reassurance-seeking have had a significant impact on the respondents’ goal-directed behavior for nature-based outdoor leisure activities during the pandemic. The theoretical contribution is that extended goal-directed behavior expands with the inclusion of emotional variables and can be used to predict individual outdoor activity intention and decision-making process in the COVID-19 situation relating to leisure. This study provides useful insights for public health ministries and local governments in any country to encourage nature-based outdoor leisure activities as a public health policy for the mental health of the people.

A highly accurate CO2ab initiodipole moment surface (DMS), Ames-2021, is reported along with 12C16O2infrared (IR) intensity comparisons approaching a 1–4‰ level of agreement and uncertainty. The Ames-2021 DMS was accurately fitted from CCSD(T) finite-field dipoles computed with the aug-cc-pVXZ (X = T, Q, 5) basis for C atom and the d-aug-cc-pVXZ (X = T, Q, 5) basis for O atoms, and extrapolated to the one particle basis set limit. Fitting σrmsis 3.8 × 10–7au for 4443 geometries below 15 000 cm–1. The corresponding IR intensity, SAmes-2021, are computed using the Ames-2 potential energy surface (PES), which is the best PES available for CO2. Compared to high accuracy IR studies for 2001i–00001 and 3001i–00001 bands, SAmes-2021matches NIST experiment-based intensities [SNIST-HIT16or SHIT20] to −1.0 ± 1.3‰, or matches DLR experiment-based intensities [SDLR-HIT16/UCL/Ames] to 1.9 ± 3.7‰. This indicates the systematic deviations and uncertainties have been significantly reduced in SAmes-2021. The SUCL2015(or SHITRAN2016) have larger deviations (vs SDLR) and uncertainties (vs SDLR, SNIST) which are attributed to the less accurate Ames-1 PES adopted in UCL-296 line list calculation. The SAmes-2021intensity of 12C16O2and 13C16O2is utilized to derive new absolute 13C/12C ratios for Vienna PeeDee Belemnite (VPDB) with uncertainty reduced by 1/3or 2/3. Further evaluation of SAmes-2021intensities are carried out on those CO2bands discussed in the HITRAN2020 update paper. Consistent improvements and better accuracies are found in band-by-band analysis, except for those bands strongly affected by Coriolis couplings, or very weak bands measured with relatively larger experimental uncertainties. The Ames-2021 296 K IR line lists are generated for 13 CO2isotopologues, with 18 000 cm–1and S296 K> 1 × 10–31cm/molecule cutoff and then combined with CDSD line positions (except 14C16O2). The Ames-2021 DMS and 296 K IR line lists represent a major improvement over previous CO2theoretical IR intensity studies, including Ames-2016, UCL-296, and recent UCL DMS 2021 update. A real 1 permille level of agreement and uncertainty will definitely require bothmore accurate PES andmore accurate DMS.

Brand authenticity is generally considered to have a direct impact on brand loyalty. However, few studies have investigated the mediating variables between them. To add to our knowledge in this area the present study examines how brand authenticity (the four dimensions of symbolism, credibility, integrity, and continuity) influences self-enhancement values (including achievement and power) and brand attachment, the antecedents to brand loyalty in chain coffee shops. This important research is carried out in the context of stimulus-organism-response (SOR) theory. The study surveyed chain coffee shop customers and a total of 410 valid responses were collected in December 2020. These were analyzed using the SPSS and AMOS statistical packages. A SEM (Structural Equation Modeling) analysis showed that all four brand authenticity elements were reliable and successful predictors of self-enhancement, which in turn leads to brand loyalty. Furthermore, all the symbolism, credibility, integrity, and continuity dimensions had a more significant impact on perceived power than achievement. Self-enhancement and brand attachment also contributed significantly to brand loyalty. Moreover, the importance of perceived achievement and power mediated the effect of brand authenticity on brand attachment. Based on these findings, this study provides important information for the management of affordable luxury service brands of coffee and other products.

The characteristics of the CH stretching and out-of-plane bending modes in polycyclic aromatic hydrocarbon molecules are investigated using anharmonic density functional theory (DFT) coupled to a vibrational second-order perturbation treatment taking resonance effects into account. The results are used to calculate the infrared emission spectrum of vibrationally excited species in the collision-less environment of interstellar space. This model follows the energy cascade as the molecules relax after the absorption of a UV photon in order to calculate the detailed profiles of the infrared bands. The results are validated against elegant laboratory spectra of polycyclic aromatic hydrocarbon absorption and emission spectra obtained in molecular beams. The factors which influence the peak position, spectral detail, and relative strength of the CH stretching and out-of-plane bending modes are investigated, and detailed profiles for these modes are derived. These are compared to observations of astronomical objects in space, and the implications for our understanding of the characteristics of the molecular inventory of space are assessed.

To understand where the Army Nonlethal Weapons (NLW) Program is going, a brief history of a nonlethal timeline from inception to date is needed. There was no Department of Defense [...]

This study investigates the content of the co-creation of tourism experiences and measures the substance of those experiences. It lays the framework for future research by providing a systematic assessment scale for co-creative tourism experiences. The scale obtained from the research is constructed using information on the entertainment, immersion, achievement, novelty, authenticity, uniqueness, education, and interaction variables found in the co-creation experience. The findings were obtained from semi-structured interviews with tourism opinion leaders and a questionnaire survey that yielded 682 responses. This study serves as a pioneering investigation of these constructs in an empirical way with statistical evidence to make the research outcome more objective. It provides tourism industry practitioners with directions on how to conduct co-creative activities, as well as how to understand the distinctive experiential contents of visitors in co-creative activities. The study enriches the tourism experience and supplies insights into the experiential marketing of the tourism industry.

We review the Best Theory + Reliable High-Resolution Experiment (BTRHE) strategy for obtaining highly accurate molecular rovibrational line lists with InfraRed (IR) intensities. The need for highly accurate molecular rovibrational line lists is twofold: (a) assignment of the many rovibrational lines for common stable molecules especially those that exhibit a large amplitude motion, such as NH3, or have a high density of states such as SO2; and (b) characterization of the atmospheres of exoplanets, which will be one of the main areas of research in astronomy in the coming decades. The first motivation arises due to the need to eliminate lines due to common molecules in an astronomical observation in order to identify lines from new molecules, while the second motivation arises due to the need to obtain accurate molecular opacities in order to characterize the atmosphere of an exoplanet. The BTRHE strategy first consists of using high-quality ab initio quantum-chemical methods to obtain a global potential energy surface (PES) and dipole moment surface (DMS) that contains the proper physics. The global PES is then refined using a subset of the reliable high-resolution experimental data. The refined PES then gives energy-level predictions to an accuracy similar to the reproduction accuracy of the experimental data used in the refinement step in the interpolation region (i.e., within the range of the experimental data used in the refinement step). The accuracy of the energy levels will slowly degrade as they are extrapolated to spectral regions beyond the high-resolution experimental data used in the refinement step. However, because the degradation is slow, the predicted energy levels can be used to assign new high-resolution experiments, and the data from these can then be used in a subsequent refinement step. In this way, the global PES eventually can yield highly accurate energy levels for all desired spectral regions including to very high energies and high Jvalues. We show that IR intensities computed with the BTRHE rovibrational wave functions and the DMS can be very accurate provided one has minimized the fitting error of the DMS and tested the completeness of the DMS. Some examples of our work on NH3, CO2, and SO2are given to highlight the usefulness of the BTRHE strategy and to provide ideas on how to further improve its predictive power in the future. In particular, it is shown how successive refinement steps, once new high-resolution data are available, can lead to PESs that yield highly accurate transition energies to larger spectral regions. The importance of including nonadiabatic corrections to reduce the J-dependence of errors for H-containing molecules is shown with work on NH3. Another very important aspect of the BTRHE approach is the consistency across isotopologues, which allows for highly accurate line lists for any isotopologue once one is obtained for the main isotopologue (which has more high-resolution data available for refinement).

This study aims to address a gap in the hospitality literature by exploring how the multifaceted and richly blended nature of cultural elements in both Western and Eastern cultures is combined within luxury hotels to meet consumers' needs. A conceptual framework is developed and examined to delineate how cultural travel motivation influences luxury hotel consumers' interest in cultural factors and in turn affects their existential authenticity, hotel image, perceived value, satisfaction, and brand loyalty. A self-administered questionnaire was adopted for data collection from hotel consumers in the Six Senses Hotel Resort in China, registered as a UNESCO World Cultural Heritage Site. It examined cultural motivation, cultural interest, and attitudes to experiential authenticity, hotel image, satisfaction and loyalty. The results enhance the understanding of the mechanism by which cognitive cultural motivation and interest have significant effects on the emotional bonds that can form between consumers’ existential authenticity, hotel image and perceived value.

Hydrofluorocarbons (HFCs) are potent greenhouse gases that are potential substitutes for ozone depleting substances. The Kigali amendment lists 17 HFCs that are currently in commercial use to be regulated under the Montreal Protocol. Future commercial applications may explore the use of other HFCs, most of which currently lack an evaluation of their climate metrics. In this work, atmospheric lifetimes, radiative efficiencies (REs), global warming potentials (GWPs), and global temperature change potentials (GTPs) for all saturated HFCs with fewer than 5 carbon atoms are estimated to help guide future usage and policy decisions. Atmospheric lifetimes were estimated using a structure activity relationship (SAR) for OH radical reactivity and estimated O(1D) reactivity. Radiative metrics were obtained using theoretically calculated infrared absorption spectra that were presented in a previous work. Calculations for some additional HFCs not included in the previous work were performed in this work. The HFCs display unique infrared spectra with strong absorption in the Earth’s atmospheric infrared window region, primarily due to the C–F stretching vibration. Results from this study show that the HFC global atmospheric lifetimes and REs are dependent upon their H atom content and molecular structure. Therefore, the HFC radiative metric evaluation requires a case-by-case evaluation. A thorough experimental evaluation of a targeted HFC’s atmospheric lifetime and climate metrics is always highly recommended. However, in cases where it is experimentally difficult to separate isomers, the new results from this study should help guide the experiments, as well as provide relevant climate metrics with uncertainties and policy relevant data.

Nitrogen-containing ions and molecules in the gas phase have been detected in non-Earth environments such as dark molecular clouds and more recently in the atmosphere of Saturn’s moon Titan. These molecules may serve as precursors to larger heterocyclic structures that provide the foundation of complex biological molecules. On Titan, molecules of m/z66 have been detected by the Cassini mission, and species of the empirical formula C4H4N may contribute to this signature. We have characterized seven isomers of C4H4N in anionic, neutral radical, and cationic states using density functional theory. Structures were optimized using the range-separated hybrid ωB97X-V with the cc-pVTZ and aug-cc-pVTZ basis sets. Anionic and radical C4H4N favor cyclic structures with aromatic and quasi-aromatic electron arrangements, respectively. Interestingly, ionization from the radical surface to the cation induces significant changes in structural stability, and the global minimum for positively charged isomers is CH2CCHCNH+, a pseudo-linear species reminiscent of cyanoallene. Select formation pathways to these structures from Titan’s existing or postulated gas-phase species, reactions that are also relevant for other astrophysical environments, are discussed. By characterizing C4H4N isomers, we have identified energetically stable anionic, radical, and cationic structures that may be present in Titan’s atmosphere and dark molecular clouds.

The azirinyl cation is an aromatic cyclic molecule that is isoelectronic with cyclopropenylidene, c-C3H2, and c-C3H3+. Cyclopropenylidene has been shown to be ubiquitous, existing in many different astrophysical environments. Given the similar chemistry between C and N, and the relative abundances between C and N in astrophysical environments, it is expected that there should be aromatic ringed molecules that incorporate N in the ring, but as yet, no such molecule has been identified. To address this issue, the present study uses high levels of electronic structure theory to compute a highly accurate quartic force field (QFF) for the azirinyl cation and its two lowest lying isomers, the cyanomethyl and isocyanomethyl cations. The theoretical approach uses the singles and doubles coupled-cluster method that includes a perturbative correction for connected triple excitations, CCSD(T), together with extrapolation to the one-particle basis set limit and corrections for scalar relativity and core-correlation. The QFF is then used in a second-order vibrational perturbation theory analysis (VPT2) to compute the fundamental vibrational frequencies and rovibrational spectroscopic constants for all three C2NH2+isomers. The reliability of the VPT2 vibrational frequencies is tested by comparison to vibrational configuration interaction (VCI) calculations, and excellent agreement is found between the two approaches. Fundamental vibrational frequencies and rovibrational spectroscopic constants for all singly substituted 13C, 15N, and D isotopologues are also reported. It is expected that the highly accurate spectroscopic data reported herein will be useful in the identification of these cations in high-resolution experimental or astronomical observations.

Building on previous studies involving coupled cluster quartic force fields for the description of spectroscopic constants and vibrational frequencies of astronomically relevant molecules, this work applies the same techniques to the elucidation of such properties for the bent 1 3A0 state of HCN and the isoelectronic 1 3A0 HCO+. Core correlation is treated both explicitly and as a correction. Each approach gives closely comparable spectroscopic constants and vibrational frequencies once more indicating that the composite method is a viable and less costly alternative. We are providing fundamental vibrational frequencies for these systems where agreement with experiment in previous studies has been within 4 cm-1 or better. Frequencies for the first overtones and combination bands as well as various spectroscopic constants are also reported.

ABSTRACTThailand and Malaysia are in a Southeast Asia Region that builds cooperative tourism promotion under the ASEAN Tourism Connectivity framework. The two countries must utilize their unique identities to build differentiation in their sales and promotion schemes but keep their coherence and co-promotion. While Thailand has paid attention to Thai herbs for physical and mind therapy, Malaysia has put its emphasis on the spa industry. Moreover, the two have introduced integration between Phuket and Langkawi to provide effective health and wellness connectivity destinations. Such cooperation will help to boost tourism connectivity within Southeast Asian countries. This paper aims to reach a clear understanding of how each country uses health and wellness tourism to attract tourists both domestically and internationally so that such cooperation and connectivity will help to promote the industry. The study identified health and wellness tourism connectivity between Thailand and Malaysia. http://travel.earth/wellness-tourism-southeast-asia

This study examines Korean tourists' experience of English as a Lingua Franca (ELF) in overseas travel using grounded theory. The data is based on semi-structured interviews with 17 South Korean tourists, and the analysis using paradigm theory demonstrated 146 concepts, 29 subcategories, 11 main categories, and a core category entitled ‘enhancing the quality of tourism experiences and the motivation for English learning through effective communicative accommodation’ regarding ELF. The findings show that despite their awareness of the growing role of ELF, participants had concerns about using English in overseas travel and had experienced language barriers. However, these were mainly caused by different linguistic expression (dialects, accents) among speakers, not from using English per se. To overcome miscommunication, participants employ diverse strategies, which contribute to enhancing the quality of tourist experiences and raising the motivation for learning English. The study makes theoretical and practical recommendations to promote effective intercultural communication between tourists and hosts for sustainable destination management.

The structures and spectroscopic properties of azirine (C2H3N), a nitrogen-containing three-membered cyclic molecule, and its isomers were studied with state-of-the-art ab initio quantum chemical methods. Azirine is isomeric with methyl cyanide (CH3CN) and methyl isocyanide (CH3NC)—both observed in the star-forming regions of Sgr B2. In this study, we characterize the stationary points on the potential energy surface, relative energies, dipole moments, rotational constants, and harmonic vibrational frequencies of the 2H-azirine (a), 1H-2,2H-azirine (b, carbene isomer), and 1H-azirine (c) cyclic isomers. The CCSD(T) method and density functional theory (DFT), using the ωB97-X functional, along with Dunning’s cc-pVXZ (X = T and Q) basis sets were used to optimize molecular geometries and calculate vibrational frequencies. The 2H-azirine, an imine isomer (a), was found to be the lowest in energy among the cyclic isomers, followed by the carbene isomer (b), and last the 1H-azirine, an enamine isomer (c). All three cyclic isomers have a Cssymmetry equilibrium structure. Azirines, if identified (three linear C2H3N isomers are already identified in the same source toward the galactic center, Sgr B2), would be the first nitrogen-containing cyclic molecules identified in an astronomical observation.

Truncated, correlated, wave function methods either produce imaginary frequencies (in the extreme case) or nonphysically low frequencies in out-of-plane motions for carbon and adjacent atoms when the carbon atoms engage in π bonding. Cyclopropenylidene is viewed as the simplest aromatic hydrocarbon, and the present as well as previous theoretical studies have shown that this simple molecule exhibits this behavior in the two out-of-plane bends (OPBs). This nonphysical behavior has been treated by removing nearly linear dependent basis functions according to eigenvalues of the overlap matrix, by employing basis sets where the spdspace saturatation is balanced with higher angular momentum functions, by including basis set superposition/incompleteness error (BSSE/BSIE) corrections, or by combining standard correlation methods with explicitly correlated methods to produce hybrid potential surfaces. However, this work supports the recently described hypothesis that the OPB problem is both a method and a basis set effect. The correlated wave function’s largest higher-order substitution term comes from a π → π* excitation where constructive interference of both orbitals artificially stabilizes the OPB. By employing schema to overcome this issue, the symmetric OPB ν9is the predicted to be the second-brightest transition, and it will be observed very close to 775 cm–1. However, more work from the community is required to formulate better how carbon atoms interact with their adjacent atoms in π-bonded systems. Such bonds are ubiquitous in all of chemistry and beyond.

AbstractThis study identifies the socio-demographic factors that affect residents’ perceptions of casino development in Singapore and how these perceptions affect support for the development. The results identified that gender, age, marital status, number of children, education, length of residency, religion and frequency of gambling significantly affected perceptions of the casino development. The level of perceived positive and negative impacts significantly affected support for the casino development. This is the first in-depth study of resident attitudes towards the newly developed casino in Singapore and contributes to the resident attitudes literature, social exchange theory and quality of life (QOL) studies in a gambling destination.

Using Hiroshima and Nagasaki as case studies, this paper explores the extent to which sites of atomic bomb explosions have been memorialized and embedded in tourism promotion for educational purposes. Findings from interviews with government officers and discourse analysis of tourism brochures highlight the complexity of using former atomic bomb sites in the context of contemporary Japan. These findings reveal four themes aligned in two pairs: tourism–education and war–peace. These themes are intertwined with the historical context of the two cities. As a tourist destination, conservative Hiroshima centers on the remembrance of the atomic tragedy and the traditional or nostalgic aspects of Japanese culture, whereas relatively liberal Nagasaki presents itself as a melting pot of cultures. Both cities retain their central role of publicly commemorating the victims of the atomic bomb for the Japanese.

This study examines the relationships between brand evidence, brand hearsay, brand distinctiveness, and brand citizenship behavior. The study identifies the crucial factors of brand evidence and brand hearsay they induce customer brand distinctiveness perception. It also investigates whether brand distinctiveness influences brand citizenship behavior. A self-administered survey was conducted with visitors (n=226) to the Busan Exhibition and Convention Center (BEXCO) in South Korea. The results demonstrate that five components of brand evidence and two components of brand hearsay have significant influence on brand distinctiveness, while one component of brand hearsay, namely publicity, has no significant influence on brand distinctiveness. In addition, brand distinctiveness has a substantial influence on brand citizenship behavior. The results of this study contribute insights into the effect of each component of brand evidence and brand hearsay on brand citizenship behavior mediated by brand distinctiveness.

Silacyclopropynylidene, SiC2, is a known and highly abundant circumstellar molecule. Its spectrum has been established as a major component of lines observed toward the carbon-rich star IRC +10216 (CW Leonis). It has been detected in its low-lying v3=1and 2 vibrational states as well as in various isotopic compositions. Increasing sensitivity and spatial resolution will enable many more emission or absorption lines to be detected. In order to detect new molecular species, unassigned lines of known species must be identified. This work uses established ab initioquartic force fields to produce data necessary for this classification of lines related to SiC2. Agreement between the theoretical vibrational frequencies and known rotational and spectroscopic constants is quite good, as good as 5 cm−1and 3 MHz, respectively in some cases. In addition, experimentally unknown vibrational frequencies and rotational constants are provided for the first overtones and combination bands in addition to 3ν3, the second overtone of the low-lying antisymmetric stretch/carbide rotation mode. Frequencies of v3=3low-Jrotational transitions of the main isotopic species are also estimated from published data for v3≤ 2. Further, we determine rotational and centrifugal distortion parameters for which in most cases vibrational effects due to the ν3mode were reduced to first, and in several cases also to second order. These values may approximate equilibrium values better than the ground state values. The data produced herein will aid in the experimental and observational characterization of this known astromolecule in order to identify some of the unassigned lines for a known entity.

Massive stars disrupt their natal molecular cloud material through radiative and mechanical feedback processes. These processes have profound effects on the evolution of interstellar matter in our Galaxy and throughout the universe, from the era of vigorous star formation at redshifts of 1–3 to the present day. The dominant feedback processes can be probed by observations of the Photo-Dissociation Regions (PDRs) where the far-ultraviolet photons of massive stars create warm regions of gas and dust in the neutral atomic and molecular gas. PDR emission provides a unique tool to study in detail the physical and chemical processes that are relevant for most of the mass in inter- and circumstellar media including diffuse clouds, proto-planetary disks, and molecular cloud surfaces, globules, planetary nebulae, and star-forming regions. PDR emission dominates the infrared (IR) spectra of star-forming galaxies. Most of the Galactic and extragalactic observations obtained with the James Webb Space Telescope (JWST) will therefore arise in PDR emission. In this paper we present an Early Release Science program using the MIRI, NIRSpec, and NIRCam instruments dedicated to the observations of an emblematic and nearby PDR: the Orion Bar. These early JWST observations will provide template data sets designed to identify key PDR characteristics in JWST observations. These data will serve to benchmark PDR models and extend them into the JWST era. We also present the Science-Enabling products that we will provide to the community. These template data sets and Science-Enabling products will guide the preparation of future proposals on star-forming regions in our Galaxy and beyond and will facilitate data analysis and interpretation of forthcoming JWST observations.

This study creates a business development model for street food tourism using data collected from Yaowarat Road and Khao San Road, in Bangkok, Thailand and the application of Kotler's marketing mix factors model. The 415 respondents were made up of 210 Thai and 205 foreign tourists and had an average age of 33 years. The research tools used were a summated rating scale questionnaire for the tourists and in-depth interviews that were conducted with fifteen respondents including six international tourists, three tour guides and six street food business owners. Basic statistics, inferential statistics and content analysis were used to analyze the data. This research was conducted in three languages (Thai, Chinese and English). The results support a business development model of street food stalls on Yaowarat Road and Khao San Road that can be applied to other areas in Bangkok or in any Asian Country that wishes to develop street food tourism as a niche tourist attraction by focusing on price, people, process, product, and physical evidence respectively to understand why street foods are capturing the interest of tourists.

Identifying new nitrogenated hydrocarbon molecules in the interstellar medium (ISM) is challenging because of the lack of comprehensive spectroscopic data from experiments. In this computational work, we focus on investigating the structures, relative energies, spectroscopic constants, and energy landscape of the cyclic isomers of diazirine (c-CH2N2) using ab initioquantum chemical methods. Density functional theory (DFT) methods and coupled cluster theory with singles and doubles including perturbative triples [CCSD(T)] and CCSD(T) with the explicitly correlated F12b correction [CCSD(T)-F12b] were employed for this purpose along with large correlation consistent cc-pVTZ, cc-pVQZ, and cc-pV5Z basis sets. Harmonic vibrational frequencies, infrared vibrational intensities, rotational constants, and dipole moments are reported. Anharmonic vibrational fundamentals along with centrifugal distortion constants, and vibration–rotation interaction constants are also reported for all the cyclic isomers. The energies computed with the CCSD(T) and CCSD(T)-F12b methods were extrapolated to the one-particle complete basis set (CBS) limit following a three-point formula. At the CCSD(T)-F12b/CBS level of theory, the 3,3H-diazirine (c-CH2N2) is the lowest energy cyclic isomer followed by 1,3H-diazirine, (E)-1,2H-diazirine, and (Z)-1,2H-diazirine, which are 20.1, 47.8, and 51.3 kcal mol–1above the 3,3H-diazirine, respectively. Accurate structures and spectroscopic constants that are reported here could be useful for future identification of these cyclic nitrogenated organic molecules in the interstellar medium or circumstellar disks.

The near-infrared (NIR) spectra and absolute band strengths of 10 nitrogenated polycyclic aromatic hydrocarbon (PANH) radical cations isolated in an argon matrix are presented and compared with the spectra of their parent polycyclic aromatic hydrocarbon (PAH) radical cations. The 0.7-2.5 mm (14,500-4000 cm[?]1) spectrum for the open-shell cation forms of two nitrogenated anthracenes (C13H9N and C12H8N2), four isomeric nitrogenated benzanthracenes (C17H11N), and four isomeric nitrogenated dibenzanthracenes (C21H13N) are reported. These ionized PANHs have allowed electronic transitions that give rise to strong absorption bands in the NIR. Low-lying excited states for these PANH ions are computed using time-dependent density functional theory (TDDFT). The resulting vertical excitation spectrum characterizes the transitions, and leads to a simple model that predicts the qualitative trends in absorption energy. The direction of the shift depends on the position of the nitrogen atom within the PANH and the relative magnitudes of the donor and acceptor molecular orbitals involved in the transitions. As with non-nitrogenated PAHs, ionized interstellar PANHs can be expected to contribute to the mid-IR emission features from UV-rich as well as UV-poor regions, and add weak, broad band structure to the NIR region of the interstellar extinction curve.

We investigate the electronic absorption spectra of several maximally pericondensed polycyclic aromatic hydrocarbon radical cations with time-dependent density functional theory calculations. We find interesting trends in the vertical excitation energies and oscillator strengths for this series containing pyrene through circumcircumcoronene, the largest species containing close to 100 carbon atoms. We discuss the implications of these new results for the size and structure distribution of the diffuse interstellar band carriers.

This study aims to evaluate the economic value of urban forests that are used as daily leisure spaces in cities, focusing on the healing value for tourists associated with their public health and environmental functions. To this end, an onsite survey of residents was conducted in Seoul, Korea. In real-world scenarios, willingness-to-pay (WTP) is associated with building a preservation fund and in this case is US$27 per capita per year, and the total fund value obtained is US$530 million, depending on whether the calculation is made using mean WTP or truncated WTP. The findings of this study suggest that urban residents determine the preservation value of urban forests according to how they feel about them. This is in terms of their restorative effect, their ability to absorb particulate matter, and the recreational satisfaction that they bring. The findings also imply that the healing functions of urban forests used mainly as leisure spaces for health promotion reasons are directly reflected in their preservation value. On the other hand, the fact that policies related to the new environmental paradigm (NEP) were found to be insignificant in all three scenarios suggests that it is necessary to educate urban residents about the environmental function of urban forests.

Summary The Ca3 and Ca4 metallic clusters have been investigated using state-of-the-artab initio quantum mechanical methods. Large atomic natural orbital basis sets have been used in conjunction with the singles and doubles coupled-cluster (CCSD) method, a coupled-cluster method that includes a perturbational estimate of connected triple excitations, denoted CCSD(T), and the multireference configuration interaction (MRCI) method. The equilibrium geometries, binding energies and harmonic vibrational frequencies have been determined with each of the methods so that the accuracy of the coupled-cluster methods may be assessed. Since the CCSD(T) method reproduces the MRCI results very well, cubic and quartic force fields of Ca3 and Ca4 have been determined using this approach and used to evaluate the fundamental vibrational frequencies. The infrared intensities of both thee' mode of Ca3 and thet2 mode of Ca4 are found to be small. The results obtained in this study are compared and contrasted with those from our earlier studies on small Be and Mg clusters.

Summary Three previously reported algorithms for the evaluation of the fourth-order triple excitation energy component in many-body perturbation theory have been compared. Their implementation on current Intel distributed memory parallel computers has been investigated. None of the algorithms, which were developed for shared memory computer architectures, performed well since they lead to prohibitive IO demands. A new algorithm suitable for distributed memory machines is suggested and its implementation on two Intel i860 supercomputers is described. A high level of parallelism is obtained.

For more than a few molecular electronic states, the simplest qualitatively correct picture of the electronic structure is provided by the two-configuration self-consistent-field (TCSCF) method. Here, analytic methods are reported for the evaluation of TCSCF infrared intensities and polarizabilities. These new methods have been implemented and applied to the molecules CH2(1A1), CF2, CH3-, NH3, HF and O3. Nine different basis sets, ranging from 3–21G to triple zeta plus double polarization (TZ + 2P), have been used. In several cases one finds qualitative differences between the analogous SCF and TCSCF predictions.

Abstract.: The equilibrium geometries, harmonic frequencies, dipole moments, infrared intensities, and relative energies of the cis-XONO, trans-XONO, and XNO2 (X=F, Cl, and Br) have been investigated using four functionals in common use in Kohn-Sham density functional theory (DFT) calculations. Two of the functionals include non-local or gradient correction terms, while the other two also incorporate some exact Hartree-Fock exchange and are labeled hybrid functionals. The quality of the results obtained from the functionals is determined by comparison to previously published high-level coupled-cluster calculations. The hybrid functionals perform better for prediction of the equilibrium geometries, where the two gradient corrected functionals yield qualitatively incorrect molecular structures for cis-FONO and cis-ClONO. None of the functionals perform well in predicting all six harmonic frequencies, showing that the correlation between equilibrium geometries and harmonic frequencies is not as strong for these DFT methods as it is for conventional wavefunction ab initio methods, such as coupled-cluster theory. Results from the various functionals generally come into better agreement with each other and also with the coupled-cluster results moving down the periodic table.

The recent detection of ethynyl-functionalized cyclopropenylidene (c-C3HC2H) has initiated the search for other functional forms of cyclopropenylidene (c-C3H2) in space. There is existing gas-phase rotational spectroscopic data for cyano-cyclopropenylidene (c-C3HCN), but the present work provides the first anharmonic vibrational spectral data for that molecule, as well as the first full set of both rotational and vibrational spectroscopic data for fluoro- and chloro-cyclopropenylidenes (c-C3HF and c-C3HCl). All three molecules have fundamental vibrational frequencies with substantial infrared intensities. Namely, c-C3HCN has a moderately intense fundamental frequency at 1244.4 cm–1, while c-C3HF has two large intensity modes at 1765.4 and 1125.3 cm–1and c-C3HCl again has two large intensity modes at 1692.0 and 1062.5 cm–1. All of these frequencies are well within the spectral range covered by the high-resolution EXES instrument on NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA). Further, all three molecules have dipole moments of around 3.0 D in line with c-C3H2, enabling them to be observed by pure rotational spectroscopy, as well. Thus, the rovibrational spectral data presented herein should assist with future laboratory studies of functionalized cyclopropenylidenes and may lead to their interstellar or circumstellar detection.

A feasible initiation step for particle growth in the interstellar medium (ISM) is simulated by means of ab initio quantum chemistry methods. The systems studied are dimer ions formed by pairing nitrogen containing small molecules known to exist in the ISM with ions of unsaturated hydrocarbons or vice versa. Complexation energies, structures of ensuing complexes and electronic excitation spectra of the encounter complexes are estimated using various quantum chemistry methods. Møller-Plesset perturbation theory (MP2), Z-averaged perturbation theory (ZAPT2), coupled cluster singles and doubles with perturbative triples corrections (CCSD(T)), and density functional theory (DFT) methods (B3LYP) were employed along with the correlation consistent cc-pVTZ and aug-cc-pVTZ basis sets. Two types of complexes are predicted. One type of complex has electrostatic binding with moderate (7−20 kcal mol-1) binding energies, that are nonetheless significantly stronger than typical van der Waals interactions between molecules of this size. The other type of complex develops strong covalent bonds between the fragments. Cyclic isomers of the nitrogen containing complexes are produced very easily by ion-molecule reactions. Some of these complexes show intense ultraviolet-visible spectra for electronic transitions with large oscillator strengths at the B3LYP, ωB97, and equations of motion coupled cluster (EOM-CCSD) levels. The open shell nitrogen containing carbonaceous complexes especially exhibit a large oscillator strength electronic transition in the visible region of the electromagnetic spectrum.