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ABSTRACT: The ground-state structures of neutral, cationic, and anionic phosphorus clusters P(n), P(n)(+), and P(n)(-) (n = 3-15) have been calculated using the B3LYP/6-311+G* density functional method. The P(n)(+) and P(n)(-) (n = 3-15) clusters with odd n were found to be more stable than those with even n, and we provide a satisfactory explanation for such trends based on concepts of energy difference, ionization potential, electron affinity, and incremental binding energy. The result of odd/even alternations is in good accord with the relative intensities of cationic and anionic phosphorus clusters observed in mass spectrometric studies.
The Journal of Physical Chemistry A 02/2007; 111(2):216-22. · 2.95 Impact Factor
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ABSTRACT: Making use of the software of molecular graphics, we designed numerous models of C(n)()Be(2-) (n = 4-14). We carried out geometry optimization and calculation on vibration frequency by means of the B3LYP density functional method. After comparison of structure stability, we found that the ground-state isomers of C(n)()Be(2-) (n = 4-14) are linear with the beryllium atom located inside the C(n)() chain. When a side carbon chain is with an even number of carbon atoms, it is polyacetylene-like, whereas when a side chain is with an odd number of carbon atoms, it is cumulene-like. The C(n)Be(2-) (n = 4-14) clusters with an even number of carbon atoms are more stable than that with an odd number of carbon atoms, matching the peak pattern observed in accelerator mass spectrometry (AMS) and Coulomb Explosion Imaging (CEI) investigations of C(n)()Be(2-) (n = 4-14). The trend of such odd/even alternation is explained based on concepts of bonding characteristics, electronic configuration, electron detachment, and incremental binding energy.
The Journal of Physical Chemistry A 05/2006; 110(13):4502-8. · 2.95 Impact Factor
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ABSTRACT: Structures of CnAs- (n = 1−11) clusters have been determined by means of B3LYP density functional method. A comparison of structure stability shows that the lowest-lying structures are linear, with the arsenic atom located at one end of the carbon chain. Also, the linear CnAs- (n = 1−11) anions with an odd number of carbon atoms are more stable than those with an even number, in good agreement with the peak pattern of time-of-flight investigation. The trend of such odd/even alternation is explained on the basis of concepts of electronic configurations, incremental binding energies, vertical electron detachment energies, and dissociation channels.
06/2004;
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ABSTRACT: Using molecular graphics software, we have designed numerous models of CnP3- (n = 2−8). We carried out geometry optimizations and calculations of vibrational frequency by means of the B3LYP density functional method. After comparing the total energies of the isomers, we found that the ground-state structures are straight carbon chains with a P2C ring connected at one end and a phosphorus atom at the other. The alternate behavior in electron affinity, bond length, and incremental binding energy with odd and even n match the peak pattern observed in the laser-induced mass spectra of CnP3-(n = 2−8). Other than a number of individual isomers, the structures with carbon and phosphorus atoms connected alternately are unstable. Most of the stable models have carbon units in the form of a ring or a chain connecting to different P, P2, and P3 units.
10/2003;
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ABSTRACT: Making use of molecular graphics software, we have designed numerous models of HCn+ (n = 1–10) cationic clusters, and performed geometry optimization and vibrational frequency calculation by means of the B3LYP density functional method. The linear ground-state isomers of HCn+ (n = 1–10) are found to be linear with the hydrogen atom located at one end of the carbon chain. When n is odd, the carbon chain is polyacetylene-like in configuration whereas when n is even, the carbon chain displays a polyacetylene-like structure that fades into a cumulenic-like arrangement towards the carbon end. We detected trends of odd/even alternation in electronic configuration, energy difference, ionization potential as well as in certain bond length and certain atomic charge of the linear ground-state HCn+ (n = 1–10) isomers. The results reveal that the odd-n cationic clusters are more stable than the even-n ones; they match the relative yields of HCn+ clusters as revealed in mass spectrometric investigations.
International Journal of Mass Spectrometry. 272:165-171.
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ABSTRACT: Making use of the software of molecular graphics, we designed many patterns of CnS2− (n = 6–18) models. We carried out geometry optimization and calculation on vibrational frequency by means of the B3LYP density functional method. The most probable ground-state isomers of CnS2− (n = 6–18) are linear with the sulfur atom located at one end of the Cn chain. When n is even, the isomer is polyacetylene-like. The CnS2− (n = 6–18) with even number of carbon atoms are more stable than those with odd number, matching the peak pattern observed in studies of mass spectrometry. The trend of odd/even alternation is also detected in certain bond length, atomic charge, electronic configuration, the highest vibrational frequency, energy difference, electron detachment energy, and incremental binding energy of the most probable ground-state isomers.
International Journal of Mass Spectrometry. 262:136-143.
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ABSTRACT: Making use of molecular graphics software, we designed numerous models of BeCn− (n = 1–8). Geometry optimization and calculation on vibration frequency were carried out by the B3LYP density functional method. After comparison of structure stability, we found that the ground-state isomers of BeCn− (n = 1–8) are linear with the beryllium atom located at one end of the Cn chain, except that the linear BeC5− isomer is slightly higher in energy than the planar cyclic BeC5− isomer. When n is even, the Cn chain of BeCn− (n = 1–8) is polyacetylene-like whereas when at odd n, the carbon chain is cumulene-like. The BeCn− (n = 1–8) with even n are found to be more stable than those with odd n, and the result is in good accord with the relative intensities of BeCn− (n = 1–8) observed in mass spectrometric studies. In this paper, we provide satisfactory explanation for such trend of even/odd alternation based on concepts of bonding nature, electronic configuration, electron affinity, incremental binding energy, and dissociation channels.
International Journal of Mass Spectrometry. 253:30-37.
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ABSTRACT: In this paper, we report the design of models for interstellar molecules HCnN (n = 1–17) by means of the B3LYP density functional method. We performed geometry optimization and calculation on vibrational frequency. We find that the ground-state (G-S) isomers of HCnN (n = 1–17) are with the N atom located at one end and the H atom at the other end of a Cn chain; they are all linear except for HC2N which is bent. When n is odd, the Cn chain is polyacetylene-like whereas when n is even, the Cn chain displays a structure that is cumulenic-like in the middle of the Cn chain. It is found that the G-S isomers of odd-n HCnN (n = 1–17) are more stable than those of even-n ones. The finding is in accord with the relative intensities of HCnN recorded in laboratory investigations, and in consistent with the results of objects observed in interstellar media. We provide explanations for such a trend of even/odd alternation based on concepts of the highest vibrational frequency, bonding character, electronic configuration, incremental binding energy, nucleus-independent chemical shift, and dissociation channels.
Chemical Physics.
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ABSTRACT: In this paper, we report the design of models for interstellar molecules HCnN (n = 1-17) by means of the B3LYP density functional method. We performed geometry optimization and calculation on vibrational frequency. We find that the ground-state (G-S) isomers of HCnN (n = 1-17) are with the N atom located at one end and the H atom at the other end of a C-n chain; they are all linear except for HC2N which is bent. When n is odd, the C-n chain is polyacetylene-like whereas when n is even, the C-n chain displays a structure that is cumulenic-like in the middle of the C-n chain. It is found that the G-S isomers of odd-n HCnN (n = 1-17) are more stable than those of even-n ones. The finding is in accord with the relative intensities of HCnN recorded in laboratory investigations, and in consistent with the results of objects observed in interstellar media. We provide explanations for such a trend of even/odd alternation based on concepts of the highest vibrational frequency, bonding character, electronic configuration, incremental binding energy, nucleus-independent chemical shift, and dissociation channels. (C) 2009 Elsevier B.V. All rights reserved. National Science Foundation [20873107, 20533020]
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ABSTRACT: In this paper, we report the design of numerous CnF3- (n = 1-9) models. By means of B3LYP density functional method, we carried out geometry optimization and calculation on the vibrational frequency. After comparison of structure stability, we found that the structures of ground-state (G-S) isomers of odd-n CnF3- (i.e., n = 3, 5, 7 and 9) are with the three fluorine atoms located at one end of the linear C-n chain. The G-S isomers of C2F3-, C4F3-, and C8F3- are with two fluorine atoms bonded to an end carbon of the C. chain, and one fluorine atom bonded to the adjacent carbon atom. In other words, the two carbon atoms involved in bonding to the fluorine atoms are sp(2) hybridized and the C-n chain is not linear. In the case of C6F3-, the G-S isomer is planar cyclic in structure, with each of the three carbon atoms at one side of the hexagonal C-6 ring bonded to a fluorine atom. The C-n chain of G-S CnF3- (n = 3-9; C6F3- being the exception) isomers are polyacetylene-like. It is found that the odd-n G-S CnF3- (n = 1-9) are more stable than the adjacent even-n ones. The finding is in accord with the relative intensities of C(n)F(3)(-)observed in mass spectrometric studies. We provide explanations for such trend of even/odd alternation based on concepts of the geometrical structure, bonding character, atomic charges, vertical electron detachment energy, and incremental binding energy. (C) 2009 Elsevier B.V. All rights reserved. National Science Foundation of China [20873107, 20533020]
