Amit B. Teradale, S. D. Lamani, B. Swamy, P. Ganesh, Swastika N. Das
A polymeric thin film modified electrode, that is, poly(niacinamide) modified carbon paste electrode (MCPE), was developed for the electrochemical determination of catechol (CC) by using cyclic voltammetric technique. Compared to bare carbon paste electrode (BCPE), the poly(niacinamide) MCPE shows good electrocatalytic activity towards the oxidation of catechol in phosphate buffer solution (PBS) of physiological pH 7.4. All experimental parameters were optimized. Poly(niacinamide) modified carbon paste electrode gave a linear response between concentration of CC and its anodic peak current in the range within 20.6–229.0 μM. The limit of detection (3S/M) and limit of quantification (10S/M) were 1.497 μM and 4.99 μM, respectively. From the study of scan rate variation, the electrode process was found to be adsorption-controlled. The involvement of protons and electrons in the oxidation of CC was found to be equal. The probable electropolymerisation mechanism of niacinamide was proposed. Finally, this method can be used in development of a sensor for sensitive determination of CC.
{"title":"Electrochemical Investigation of Catechol at Poly(niacinamide) Modified Carbon Paste Electrode: A Voltammetric Study","authors":"Amit B. Teradale, S. D. Lamani, B. Swamy, P. Ganesh, Swastika N. Das","doi":"10.1155/2016/8092860","DOIUrl":"https://doi.org/10.1155/2016/8092860","url":null,"abstract":"A polymeric thin film modified electrode, that is, poly(niacinamide) modified carbon paste electrode (MCPE), was developed for the electrochemical determination of catechol (CC) by using cyclic voltammetric technique. Compared to bare carbon paste electrode (BCPE), the poly(niacinamide) MCPE shows good electrocatalytic activity towards the oxidation of catechol in phosphate buffer solution (PBS) of physiological pH 7.4. All experimental parameters were optimized. Poly(niacinamide) modified carbon paste electrode gave a linear response between concentration of CC and its anodic peak current in the range within 20.6–229.0 μM. The limit of detection (3S/M) and limit of quantification (10S/M) were 1.497 μM and 4.99 μM, respectively. From the study of scan rate variation, the electrode process was found to be adsorption-controlled. The involvement of protons and electrons in the oxidation of CC was found to be equal. The probable electropolymerisation mechanism of niacinamide was proposed. Finally, this method can be used in development of a sensor for sensitive determination of CC.","PeriodicalId":7371,"journal":{"name":"Advances in Physical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80320765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We apply density functional theory at PBE/6-311G(d) level as well as nonorthogonal tight-binding model to study the Stone-Wales transformation in C36 fullerene embedded inside the (14,0) zigzag carbon nanotube. We optimize geometries of two different isomers with the and the symmetries and the transition state dividing them. The mechanism of Stone-Wales transformation from to symmetry for the encapsulated C36 is calculated to be the same as for the isolated one. It is found that the outer carbon wall significantly stabilizes the isomer. However, carbon nanotube reduces the activation barrier of Stone-Wales rearrangement by 0.4 eV compared with the corresponding value for the isolated C36.
{"title":"Theoretical Studies of the Stone-Wales Defect in C36 Fullerene Embedded inside Zigzag Carbon Nanotube","authors":"K. Grishakov, K. Katin, M. Maslov","doi":"10.1155/2016/1862959","DOIUrl":"https://doi.org/10.1155/2016/1862959","url":null,"abstract":"We apply density functional theory at PBE/6-311G(d) level as well as nonorthogonal tight-binding model to study the Stone-Wales transformation in C36 fullerene embedded inside the (14,0) zigzag carbon nanotube. We optimize geometries of two different isomers with the and the symmetries and the transition state dividing them. The mechanism of Stone-Wales transformation from to symmetry for the encapsulated C36 is calculated to be the same as for the isolated one. It is found that the outer carbon wall significantly stabilizes the isomer. However, carbon nanotube reduces the activation barrier of Stone-Wales rearrangement by 0.4 eV compared with the corresponding value for the isolated C36.","PeriodicalId":7371,"journal":{"name":"Advances in Physical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80302650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The removal of toxic dye rhodamine B (RB) from aqueous solution was achieved by using Casuarina equisetifolia cone (CEC) as an adsorbent. Batch experiment method was used in order to investigate the effects of contact time, pH, temperature, ionic strength, and dye concentration on the adsorption process. Kinetics and isotherm theoretical models were applied on the experimental data and it was found that the pseudo-2nd-order kinetics and the Langmuir isotherm model best fitted into the data. The Langmuir maximum adsorption capacity for CEC was determined as 49.5 mg g−1. The adsorption of RB onto CEC is thermodynamically favourable, feasible, and endothermic in nature.
{"title":"Remediation of Rhodamine B Dye from Aqueous Solution Using Casuarina equisetifolia Cone Powder as a Low-Cost Adsorbent","authors":"M. K. Dahri, M. R. R. Kooh, L. Lim","doi":"10.1155/2016/9497378","DOIUrl":"https://doi.org/10.1155/2016/9497378","url":null,"abstract":"The removal of toxic dye rhodamine B (RB) from aqueous solution was achieved by using Casuarina equisetifolia cone (CEC) as an adsorbent. Batch experiment method was used in order to investigate the effects of contact time, pH, temperature, ionic strength, and dye concentration on the adsorption process. Kinetics and isotherm theoretical models were applied on the experimental data and it was found that the pseudo-2nd-order kinetics and the Langmuir isotherm model best fitted into the data. The Langmuir maximum adsorption capacity for CEC was determined as 49.5 mg g−1. The adsorption of RB onto CEC is thermodynamically favourable, feasible, and endothermic in nature.","PeriodicalId":7371,"journal":{"name":"Advances in Physical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81294527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Farahani, Wei Gao, M. Kanna, R. P. Kumar, Jia-bao Liu
We present explicit formula for the general Randic connectivity, general sum-connectivity, Hyper-Zagreb and Harmonic Indices, and Harmonic polynomial of some simple connected molecular graphs.
{"title":"General Randić, Sum-Connectivity, Hyper-Zagreb and Harmonic Indices, and Harmonic Polynomial of Molecular Graphs","authors":"M. Farahani, Wei Gao, M. Kanna, R. P. Kumar, Jia-bao Liu","doi":"10.1155/2016/2315949","DOIUrl":"https://doi.org/10.1155/2016/2315949","url":null,"abstract":"We present explicit formula for the general Randic connectivity, general sum-connectivity, Hyper-Zagreb and Harmonic Indices, and Harmonic polynomial of some simple connected molecular graphs.","PeriodicalId":7371,"journal":{"name":"Advances in Physical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78403246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The industrial waste, bauxite residue generated in the Bayer chemical process of alumina production, commonly known as red mud (RM) has been used as the adsorbent for selective removal of phosphate in aqueous solutions. RM collected from the storage area of alumina industry was characterized by chemical analysis and physical methods such as BET surface area, Scanning Electron Microscopy (SEM), particle size analysis, and X-ray diffraction (XRD) methods. Among the various red mud samples (0.2–200 μ) studied, the samples treated with 1 M HCl for 2 h were found better for the selective adsorption of phosphate in comparison with untreated and heat treated RM samples. The presence of phosphate in the aqueous samples collected after adsorption studies with red mud was determined by standard spectrophotometric procedure using ammonium molybdate and ascorbic acid in nitrate medium at 880 nm. The studies reported significant adsorption of phosphate on acid treated red mud in comparison with adsorption of phosphate on untreated and heat treated red mud, respectively. The adsorption of phosphate on raw red mud and activated red mud was further investigated with respect to stirring time, pH of the solution, dose of adsorbent, and varying phosphate concentration. Acid treated RM is observed as an efficient and cost-effective adsorbent for selective removal of phosphate in aqueous solutions.
利用拜耳化工生产氧化铝过程中产生的工业废渣、铝土矿渣，俗称赤泥(RM)作为吸附剂，对水溶液中的磷酸盐进行选择性脱除。采用BET表面积、扫描电镜(SEM)、粒度分析和x射线衍射(XRD)等化学分析和物理方法对从氧化铝工业储存区收集的RM进行了表征。在所研究的赤泥样品(0.2 ~ 200 μ)中，与未经处理和热处理的赤泥样品相比，1 M HCl处理2 h的赤泥样品对磷酸盐的选择性吸附效果更好。用钼酸铵和抗坏血酸在880 nm的硝酸介质中分光光度法测定了红泥吸附后的水样品中磷酸盐的存在。这些研究分别报道了磷酸处理后的赤泥对磷酸盐的显著吸附，与未经处理和热处理的赤泥对磷酸盐的吸附相比。进一步考察了搅拌时间、溶液pH、吸附剂用量、磷酸盐浓度等因素对原料赤泥和活性赤泥吸附磷酸盐的影响。酸处理的RM被认为是一种高效和经济的吸附剂，用于选择性去除水溶液中的磷酸盐。
{"title":"Removal of Phosphate Using Red Mud: An Environmentally Hazardous Waste By-Product of Alumina Industry","authors":"S. Prajapati, P. A. Najar, V. Tangde","doi":"10.1155/2016/9075206","DOIUrl":"https://doi.org/10.1155/2016/9075206","url":null,"abstract":"The industrial waste, bauxite residue generated in the Bayer chemical process of alumina production, commonly known as red mud (RM) has been used as the adsorbent for selective removal of phosphate in aqueous solutions. RM collected from the storage area of alumina industry was characterized by chemical analysis and physical methods such as BET surface area, Scanning Electron Microscopy (SEM), particle size analysis, and X-ray diffraction (XRD) methods. Among the various red mud samples (0.2–200 μ) studied, the samples treated with 1 M HCl for 2 h were found better for the selective adsorption of phosphate in comparison with untreated and heat treated RM samples. The presence of phosphate in the aqueous samples collected after adsorption studies with red mud was determined by standard spectrophotometric procedure using ammonium molybdate and ascorbic acid in nitrate medium at 880 nm. The studies reported significant adsorption of phosphate on acid treated red mud in comparison with adsorption of phosphate on untreated and heat treated red mud, respectively. The adsorption of phosphate on raw red mud and activated red mud was further investigated with respect to stirring time, pH of the solution, dose of adsorbent, and varying phosphate concentration. Acid treated RM is observed as an efficient and cost-effective adsorbent for selective removal of phosphate in aqueous solutions.","PeriodicalId":7371,"journal":{"name":"Advances in Physical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90859670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Fawzy, Saleh A. Ahmed, I. Althagafi, M. Morad, K. Khairou
The oxidation kinetics of fluorenone hydrazone (FH) using potassium permanganate in alkaline medium were measured at a constant ionic strength of 0.1 mol dm−3 and at 25°C using UV/VIS spectrophotometer. A first-order kinetics has been monitored in the reaction of FH with respect to [permanganate]. Less-than-unit order dependence of the reaction on [FH] and [OH−] was revealed. No pronounced effect on the reaction rate by increasing ionic strength was recorded. Intervention of free radicals was observed in the reaction. The reaction mechanism describing the kinetic results was illustrated which involves formation of 1 : 1 intermediate complex between fluorenone hydrazones and the active species of permanganate. 9H-Fluorenone as the corresponding ketone was found to be the final oxidation product of fluorenone hydrazone as confirmed by GC/MS analysis and FT-IR spectroscopy. The expression rate law for the oxidation reaction was deduced. The reaction constants and mechanism have been evaluated. The activation parameters associated with the rate-limiting step of the reaction, along with the thermodynamic quantities of the equilibrium constants, have been calculated and discussed.
{"title":"Kinetics and Mechanistic Study of Permanganate Oxidation of Fluorenone Hydrazone in Alkaline Medium","authors":"A. Fawzy, Saleh A. Ahmed, I. Althagafi, M. Morad, K. Khairou","doi":"10.1155/2016/4526578","DOIUrl":"https://doi.org/10.1155/2016/4526578","url":null,"abstract":"The oxidation kinetics of fluorenone hydrazone (FH) using potassium permanganate in alkaline medium were measured at a constant ionic strength of 0.1 mol dm−3 and at 25°C using UV/VIS spectrophotometer. A first-order kinetics has been monitored in the reaction of FH with respect to [permanganate]. Less-than-unit order dependence of the reaction on [FH] and [OH−] was revealed. No pronounced effect on the reaction rate by increasing ionic strength was recorded. Intervention of free radicals was observed in the reaction. The reaction mechanism describing the kinetic results was illustrated which involves formation of 1 : 1 intermediate complex between fluorenone hydrazones and the active species of permanganate. 9H-Fluorenone as the corresponding ketone was found to be the final oxidation product of fluorenone hydrazone as confirmed by GC/MS analysis and FT-IR spectroscopy. The expression rate law for the oxidation reaction was deduced. The reaction constants and mechanism have been evaluated. The activation parameters associated with the rate-limiting step of the reaction, along with the thermodynamic quantities of the equilibrium constants, have been calculated and discussed.","PeriodicalId":7371,"journal":{"name":"Advances in Physical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89343821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The potential energy landscape of pentapeptides was mapped in a collective coordinate principal conformational subspace derived from principal component analysis of a nonredundant representative set of protein structures from the PDB. Three pentapeptide sequences that are known to be distinct in terms of their secondary structure characteristics, (Ala)5, (Gly)5, and Val.Asn.Thr.Phe.Val, were considered. Partitioning the landscapes into different energy valleys allowed for calculation of the relative propensities of the peptide secondary structures in a statistical mechanical framework. The distribution of the observed conformations of pentapeptide data showed good correspondence to the topology of the energy landscape of the (Ala)5 sequence where, in accord with reported trends, the α-helix showed a predominant propensity at 298 K. The topography of the landscapes indicates that the stabilization of the α-helix in the (Ala)5 sequence is enthalpic in nature while entropic factors are important for stabilization of the β-sheet in the Val.Asn.Thr.Phe.Val sequence. The results indicate that local interactions within small pentapeptide segments can lead to conformational preference of one secondary structure over the other where account of conformational entropy is important in order to reveal such preference. The method, therefore, can provide critical structural information for ab initio protein folding methods.
{"title":"Energy Landscape of Pentapeptides in a Higher-Order Conformational Subspace","authors":"K. ElSawy","doi":"10.1155/2016/3240674","DOIUrl":"https://doi.org/10.1155/2016/3240674","url":null,"abstract":"The potential energy landscape of pentapeptides was mapped in a collective coordinate principal conformational subspace derived from principal component analysis of a nonredundant representative set of protein structures from the PDB. Three pentapeptide sequences that are known to be distinct in terms of their secondary structure characteristics, (Ala)5, (Gly)5, and Val.Asn.Thr.Phe.Val, were considered. Partitioning the landscapes into different energy valleys allowed for calculation of the relative propensities of the peptide secondary structures in a statistical mechanical framework. The distribution of the observed conformations of pentapeptide data showed good correspondence to the topology of the energy landscape of the (Ala)5 sequence where, in accord with reported trends, the α-helix showed a predominant propensity at 298 K. The topography of the landscapes indicates that the stabilization of the α-helix in the (Ala)5 sequence is enthalpic in nature while entropic factors are important for stabilization of the β-sheet in the Val.Asn.Thr.Phe.Val sequence. The results indicate that local interactions within small pentapeptide segments can lead to conformational preference of one secondary structure over the other where account of conformational entropy is important in order to reveal such preference. The method, therefore, can provide critical structural information for ab initio protein folding methods.","PeriodicalId":7371,"journal":{"name":"Advances in Physical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89470923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper titled “(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO 2 -Based Nanomaterials” [1] contains an error in Figure 3(b) where the work function of the semiconductor, ΦS, should be depicted as the energy difference between the semiconductor Fermi level and the local vacuum level just outside the semiconductor surface. The corrected Figure 3 is shown as follows.
{"title":"Corrigendum to “(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO2-Based Nanomaterials”","authors":"R. Beranek","doi":"10.1155/2016/8235954","DOIUrl":"https://doi.org/10.1155/2016/8235954","url":null,"abstract":"The paper titled “(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO 2 -Based Nanomaterials” [1] contains an error in Figure 3(b) where the work function of the semiconductor, ΦS, should be depicted as the energy difference between the semiconductor Fermi level and the local vacuum level just outside the semiconductor surface. The corrected Figure 3 is shown as follows.","PeriodicalId":7371,"journal":{"name":"Advances in Physical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88282376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Impedance measurement was conducted at the entire cell level for studying of the Ni-MH rechargeable batteries. An improved equivalent circuit model considering diffusion process is proposed for simulation of battery impedance data at different charge input levels. The cell capacity decay was diagnosed by analyzing the ohmic resistance, activation resistance, and mass transfer resistance of the Ni-MH cells with degraded capacity. The capacity deterioration of this type, Ni-MH cell, is considered in relation to the change of activation resistance of the nickel positive electrodes. Based on the report and surface analysis obtained from the energy dispersive X-ray spectroscopy, the composition formula of metal-hydride electrodes can be closely documented as the AB5 type alloy and the “A” elements are recognized as lanthanum (La) and cerium (Ce). The capacity decay of the Ni-MH cell is potentially initiated due to starved electrolyte for the electrochemical reaction of active materials inside the Ni-MH battery, and the discharge product of Ni(OH)2 at low state-of-charge level is anticipated to have more impeding effects on electrode kinetic process for higher power output and efficient energy delivery.
{"title":"Simulation of Ni-MH Batteries via an Equivalent Circuit Model for Energy Storage Applications","authors":"Y. Zhu, Wenhua H. Zhu, Zenda Davis, B. Tatarchuk","doi":"10.1155/2016/4584781","DOIUrl":"https://doi.org/10.1155/2016/4584781","url":null,"abstract":"Impedance measurement was conducted at the entire cell level for studying of the Ni-MH rechargeable batteries. An improved equivalent circuit model considering diffusion process is proposed for simulation of battery impedance data at different charge input levels. The cell capacity decay was diagnosed by analyzing the ohmic resistance, activation resistance, and mass transfer resistance of the Ni-MH cells with degraded capacity. The capacity deterioration of this type, Ni-MH cell, is considered in relation to the change of activation resistance of the nickel positive electrodes. Based on the report and surface analysis obtained from the energy dispersive X-ray spectroscopy, the composition formula of metal-hydride electrodes can be closely documented as the AB5 type alloy and the “A” elements are recognized as lanthanum (La) and cerium (Ce). The capacity decay of the Ni-MH cell is potentially initiated due to starved electrolyte for the electrochemical reaction of active materials inside the Ni-MH battery, and the discharge product of Ni(OH)2 at low state-of-charge level is anticipated to have more impeding effects on electrode kinetic process for higher power output and efficient energy delivery.","PeriodicalId":7371,"journal":{"name":"Advances in Physical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90094434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Heat of formation is one of several important parameters used to assess the performance of energetic compounds. We evaluated the ability of six different methods to accurately calculate gas-phase heat of formation () values for a test set of 45 nitrogen-containing energetic compounds. Density functional theory coupled with the use of isodesmic or other balanced equations yielded calculated results in which 82% (37 of 45) of the values were within ±2.0 kcal/mol of the most recently recommended experimental/reference values available. This was compared to a procedure using density functional theory (DFT) coupled with an atom and group contribution method in which 51% (23 of 45) of the values were within ±2.0 kcal/mol of these values. The T1 procedure and Benson’s group additivity method yielded results in which 51% (23 of 45) and 64% (23 of 36) of the values, respectively, were within ±2.0 kcal/mol of these values. We also compared two relatively new semiempirical approaches (PM7 and RM1) with regard to their ability to accurately calculate . Although semiempirical methods continue to improve, they were found to be less accurate than the other approaches for the test set used in this investigation.
{"title":"Calculating Heat of Formation Values of Energetic Compounds: A Comparative Study","authors":"Michael S. Elioff, J. Hoy, J. Bumpus","doi":"10.1155/2016/5082084","DOIUrl":"https://doi.org/10.1155/2016/5082084","url":null,"abstract":"Heat of formation is one of several important parameters used to assess the performance of energetic compounds. We evaluated the ability of six different methods to accurately calculate gas-phase heat of formation () values for a test set of 45 nitrogen-containing energetic compounds. Density functional theory coupled with the use of isodesmic or other balanced equations yielded calculated results in which 82% (37 of 45) of the values were within ±2.0 kcal/mol of the most recently recommended experimental/reference values available. This was compared to a procedure using density functional theory (DFT) coupled with an atom and group contribution method in which 51% (23 of 45) of the values were within ±2.0 kcal/mol of these values. The T1 procedure and Benson’s group additivity method yielded results in which 51% (23 of 45) and 64% (23 of 36) of the values, respectively, were within ±2.0 kcal/mol of these values. We also compared two relatively new semiempirical approaches (PM7 and RM1) with regard to their ability to accurately calculate . Although semiempirical methods continue to improve, they were found to be less accurate than the other approaches for the test set used in this investigation.","PeriodicalId":7371,"journal":{"name":"Advances in Physical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87073067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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