Search

We report absorption, laser fluorescence, and Raman spectra for Re2 in an argon matrix prepared by the mass-selected ion deposition technique. The dirhenium absorption spectrum consists of seven band systems (A–G) extending from the near infrared into the ultraviolet region. For the A system (a simple vibrational progression), we find T0=10 817(1) cm-1, ωe=317.1(5) cm-1 and ωexe=1.0(1) cm-1. A Franck–Condon analysis of the A system intensities predicts that this state has a smaller equilibrium internuclear distance than the ground state (Δre=-0.073 Å), in violation of Badger’s rule. The B system starts at 13 250 cm-1 and consists of four overlapping (and possibly perturbed) subsystems, whose average vibrational spacing is 270(11) cm-1. The C, D, E, and F systems (vibrational spacings in parentheses) are centered at 22 300 cm-1 (210 cm-1), 24 500 cm-1 (195 cm-1), 29 150 cm-1 (175 cm-1), and 32 900 cm-1 (160 cm-1), respectively. Weak fluorescence spectra, obtained upon laser excitation into the A system, were characterized by vibrational progressions to the dimer ground (X) state and to a low lying (X’) state for which T0=357.6(5) cm-1 and ωe=332.3(2) cm-1. Raman and fluorescence progressions to the ground state were observed when the B system was excited. These data give ωe=337.9(49) cm-1 for the dimer ground state in good agreement with measurements from photodetachment spectra [J. Am. Chem. Soc. 108, 178 (1986)]. We propose likely assignments for the low lying electronic states of Re2 and discuss our results in terms of the bonding in the other group VIIB dimers, Mn2 and Tc2. [ABSTRACT FROM AUTHOR]

We have examined both the absorption and resonance Raman spectra of mass-selected Ta tetramers. The tetramers are produced in a sputtering source and mass filtered with a Wien filter, then neutralized and deposited in an Ar matrix at low temperatures. The absorption spectrum indicates two broad transitions, one in the red at 768 nm and another to the blue at 532 nm. Raman resonances could be excited in both regions giving three distinct fundamental frequencies at 270.2(1) cm-1, 185.1(1) cm-1, and 130.6(2) cm-1. The lowest vibration shows a long progression (up to seven overtones) with alternating separations of 135 cm-1 and 126 cm-1, indicative of a weak Jahn–Teller effect in the tetramer ground state. This, along with the observation that the fundamental frequency ratios are close to 2:[Square_Root]2:1 indicate that the molecule has a tetrahedral ground state geometry with an electronic E state symmetry. The appearance of three fundamentals in the resonance Raman spectrum indicates that both excited states corresponding to the observed absorption bands arise from severely distorted T electronic states. © 1995 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We report absorption and Raman spectra for cobalt dimers in an argon matrix prepared by the mass-selected ion deposition technique. A weak dimer absorption band was found between 425 and 485 nm. Resonance Raman spectra (obtained by exciting between 457.9–488.0 nm) give ωe‘= 296.8(54) cm-1 with ωexe‘ = 2.2(8) cm-1. The dicobalt data are discussed in terms of results from recent photodetachment experiments which suggest a changeover from d–d bonding to s–s bonding along the series Fe2→Cu2. © 1994 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The sensitivity of CD detection is greatly enhanced in fluorescence detected circular dichroism (FDCD), as it is based on direct measurement of emitted radiation against a zero background. An extension of FDCD to exciton coupled systems comprising identical chromophores with intense electric transition moments, is reported.

Investigates the haplotype frequencies of Y-chromosome STR loci in Chinese population. Development of a multiplex amplified for these Y-STR markers; Sufficiency of the sample size for the research purpose; Sensitivity and reliability of using non-denaturing polyacrylamide gel electrophoresis and visualized silver staining in the analysis of the PCR products.

Objective: To deduce the region that the geographical species of Lucilia sericata come from and determine the scene of crime (SOC) based on the gene analysis of mtDNA CO II., Methods: A 635 bp region for CO II of 4 Lucilia sericata (belong to 2 geographical species) were collected and sequenced, compared with the data of GenBank. A neighbour-joining tree with the Tamura and Nei model was constructed by MEGA2.1 package. The number of inherit intervals of inner-species were analyzes by Kimura's two-parameter model and used for construction the relationships between hereditary and latitude interval by SPSS10.5 soft., Results: It showed that they had the relationships between inherit and latitude interval for the 8 geographical species of Lucilia sericata for CO II., Conclusion: This method can be the evidence deducing the region that the geographical species of Lucilia sericata come from and further to determine the scene of crime (SOC).

Objective: To solve the problems of identification of Sarcosaphagous flies and their larvae, pupas and eggs., Methods: Sarcosaphagous Flies (Diptera) Samples were collected on the corpses of rabbits in the Huhhot district and a pig in the Dunhuang district. A 278bp region in the cytochrome oxidase subunit I (CO I) gene in mtDNA was analysed by DNA sequencing, A neighbour-joining tree using the Tamura and Nei model of nucleotide substitution was also constructed using the MEGA2.1 package., Results: A 278 base pairs region of the gene for CO I encoding region of mtDNA of above all samples was showed less than 1% sequence divergence within species and about 3% divergence between species., Conclusion: It is an effective, easy and accurate method to be used for identification of these Sarcosaphagous Flies (Diptera) to species group by sequencing the 278 base pairs region of the CO I encoding gene of mtDNA.

Objective: To establish a simplified method of multiplex PCR based on chimeric primers for STR loci., Methods: A set of chimeric primers and universal primers were designed to carry out a multiplex PCR for amplifying four short tandem repeats(STR) loci. Then the amplified STR loci were detected by polyacrylamide gel electrophoresis and the gels were sliverstained., Results: A quadriplex STR system was developed on the basis of both chimeric and universal primers., Conclusion: The STR multiplex PCR based on both chimeric and universal primers hss been achieved readily and reproducibly by simple adjustment of the individual primer concentrations. The use of chimeric primers provides a method for primer design that eliminates the multiple optimization steps involved in developing the multiplex PCR.

Objective: In order to determine the major species of sarcosaphagous flies and their regular activity on carcass in Hohhot district., Methods: Six rabbits were killed and placed outdoors at different time from July to October in Hohhot district. Some species of sarcosaphagous flies that appeared the cadavers were observed and identified., Results: It showed that there are 10 main spieces belonging to 3 families and 8 genera were from Diptera, including Musa domestica domestica Linnaeus, Musa domestica vicina Maequart, Ophyra capensis (Wiedemann), Hydrotaea armipes (Fall.), Muscina stabulans (Fall.) from Museidae; Lucilia sericata (Meigen), Chrysomya megacephala (Fabricius), Lucilia cuprina (Wiedemann) from Calliphoridae; Boettcherisca peregrina (Robineau-Desvoiy), Parascarcophaga crassipalpis (Maequart) from Sacrophagidae. Besides, it showed obvious regulations that different species of sarcosaphagous flies appeared on carcass at different postmortem interval and the first part of carcass that sarcosaphagous flies appeared on., Conclusion: It may be useful for estimating postmortem interval in Hohhot district.