In this paper,we examined the performance of 12 density functionals(B3LYP,X3LYP,O3LYP,PBE0,B3PW91,BLYP,OLYP,OPBE,PBE,BPW91,VSXC and TPSS),combined with two basis sets[DZP++ and 6-311+G(3df,2p)] in the prediction of th...
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In this paper,we examined the performance of 12 density functionals(B3LYP,X3LYP,O3LYP,PBE0,B3PW91,BLYP,OLYP,OPBE,PBE,BPW91,VSXC and TPSS),combined with two basis sets[DZP++ and 6-311+G(3df,2p)] in the prediction of the adiabatic electron affinities against a set of 91 well-established experimental *** have reached a conclusion that all these modern functionals are ge-nerally good,giving a mean absolute deviation(MAD)less than 0.24 eV.B3LYP and X3LYP are among the most reliable methods for this test *** the DZP++ basis set is adopted,X3LYP is the best with a MAD of 0.14 eV,while B3LYP leads to a MAD of 0.16 *** the basis set is extended to 6-311+G(3df,2p),B3LYP improves its MAD to 0.13 eV,while the MAD of X3LYP remains to be 0.14 *** hybrid functionals outperform the corresponding GGA functinals,with the exception of *** meta-GGA functionals(VSXC and TPSS)are not necessarily better than the GGA *** calculations also reveal that there are flaws associated with the OPTX exchange functional in the calculations of EA.
Effect of different alkali metal salts on the crystal size and the crystallization rate of ZSM 5 zeolite was detailedly investigated in this paper. The samples prepared by adding the different alkali metal salts were ...
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Effect of different alkali metal salts on the crystal size and the crystallization rate of ZSM 5 zeolite was detailedly investigated in this paper. The samples prepared by adding the different alkali metal salts were characterized by using XRD, TEM, TG DSC, BET and IR techniques. The XRD results showed that, for the nanosized ZSM 5 zeolite, the characteristic peaks broadened on the XRD patterns in comparison with the microsized ZSM 5 zeolite. The SEM results verified that the crystal size of zeolites prepared by adding different alkali metal salts had different results, and adding NaCl, NaC2H3O2 and KCl showed the better effect of reducing crystal size, which are about of 40～ 60nm size. The crystallization curve of adding the different alkali metal salts suggested that the crystallization rate was significantly affected by the anions in the alkali metal salt besides the cations. Moreover, the crystal size likewise depended on the anion in the alkali metal salt. In addition, the BET results suggested that the nanosized ZSM 5 zeolite possessed a larger outer surface area in comparison with the microsized ZSM 5 zeolite. The thermostability of the samples was determined by TG DSC technique, indicating that the nanosized ZSM 5 zeolite had a poor thermostability as compared with the microsized ZSM 5 zeolite. The possible difference of the samples with different crystal sizes on IR spectra was also given.
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