Pub Date : 2007-11-01DOI: 10.1163/157404007782913426
H. Matsuyama, T. Koga
Average low and high > momenta are examined for 28 singly-excited 1snl singlet and triplet states (0 ≤ l decreases with increasing n and decreasing l, while the high momentum > is nearly equal to 16/(3π)≅1.698, independent of n and l. Comparing the low and high > momenta with the average electron momentum of a hydrogenlike atom, we show that an electron with a lower momentum behaves like an nl electron of the hydrogen atom and another electron with a higher momentum behaves like the 1s electron of the helium cation. A decomposition of an uncertainty product finds that the largest contribution to comes from an outer electron and a high momentum electron, where and are the usual average electron radius and momentum, respectively.
{"title":"Average Low and High Momenta in Singly-Excited 1 snl States of the He Atom","authors":"H. Matsuyama, T. Koga","doi":"10.1163/157404007782913426","DOIUrl":"https://doi.org/10.1163/157404007782913426","url":null,"abstract":"Average low and high > momenta are examined for 28 singly-excited 1snl singlet and triplet states (0 ≤ l decreases with increasing n and decreasing l, while the high momentum > is nearly equal to 16/(3π)≅1.698, independent of n and l. Comparing the low and high > momenta with the average electron momentum of a hydrogenlike atom, we show that an electron with a lower momentum behaves like an nl electron of the hydrogen atom and another electron with a higher momentum behaves like the 1s electron of the helium cation. A decomposition of an uncertainty product finds that the largest contribution to comes from an outer electron and a high momentum electron, where and are the usual average electron radius and momentum, respectively.","PeriodicalId":101169,"journal":{"name":"Soft Computing Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88744471","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}
Pub Date : 2007-11-01DOI: 10.1163/157404007782913110
H. Torii, Masaki Yoshida
For the purpose of seeking vibrational spectroscopic signatures of the mixing of the cis conformers in liquid N-methylformamide (NMF), infrared (IR) and Raman spectra are calculated by the ab initio molecular orbital method for three clusters of NMF: linear and cyclic hexamers of the trans conformers, and a cyclic trimer of the cis conformers. It is found that a small feature at ∼250 cm−1 in the observed Raman spectrum of liquid NMF corresponds to the strongly Raman-active modes calculated at 263 cm−1 for the cis cyclic trimer. Considering that there is no vibrational mode around this frequency position for the clusters of the trans conformers, it is suggested that the Raman band at ∼250 cm−1 is a marker band of hydrogen-bonded cis conformers, and the existence of a small feature at this position in the observed Raman spectrum of liquid NMF is a vibrational spectroscopic signature indicating the mixing of the cis conformers in this liquid. However, the main features of the observed low-frequency Raman spectrum (10–400 cm−1) of liquid NMF are explained by the strongly Raman-active modes of the clusters of the trans conformers, in contradiction to the suggestion in a recent x-ray diffraction study that liquid NMF is dominated by the cis conformers. The features of the IR and Raman spectra in the amide I (C=O stretching) region are also discussed.
{"title":"Vibrational Spectroscopic Signature Indicating the Mixing of the Cis Conformers in Liquid N -Methylformamide","authors":"H. Torii, Masaki Yoshida","doi":"10.1163/157404007782913110","DOIUrl":"https://doi.org/10.1163/157404007782913110","url":null,"abstract":"For the purpose of seeking vibrational spectroscopic signatures of the mixing of the cis conformers in liquid N-methylformamide (NMF), infrared (IR) and Raman spectra are calculated by the ab initio molecular orbital method for three clusters of NMF: linear and cyclic hexamers of the trans conformers, and a cyclic trimer of the cis conformers. It is found that a small feature at ∼250 cm−1 in the observed Raman spectrum of liquid NMF corresponds to the strongly Raman-active modes calculated at 263 cm−1 for the cis cyclic trimer. Considering that there is no vibrational mode around this frequency position for the clusters of the trans conformers, it is suggested that the Raman band at ∼250 cm−1 is a marker band of hydrogen-bonded cis conformers, and the existence of a small feature at this position in the observed Raman spectrum of liquid NMF is a vibrational spectroscopic signature indicating the mixing of the cis conformers in this liquid. However, the main features of the observed low-frequency Raman spectrum (10–400 cm−1) of liquid NMF are explained by the strongly Raman-active modes of the clusters of the trans conformers, in contradiction to the suggestion in a recent x-ray diffraction study that liquid NMF is dominated by the cis conformers. The features of the IR and Raman spectra in the amide I (C=O stretching) region are also discussed.","PeriodicalId":101169,"journal":{"name":"Soft Computing Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90656037","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}
Pub Date : 2007-11-01DOI: 10.1163/157404007782913417
G. Figari, V. Magnasco
We improve a previously reported technique for interpolating available values of atomic or molecular frequency-dependent multipole polarizabilities and calculating the related dispersion constants. The improvement is provided by a simple formula allowing for an efficient selection of the frequencies involved (i.e. the frequencies implying numerical evaluations performed on the interpolated polarizability). It is shown that sensibly lower interpolative errors are obtained, so giving an enhanced accuracy in the subsequent calculation of the related dispersion constants.
{"title":"On the Efficient Selection of Frequencies for Interpolating Dynamic Multipole Polarizabilities","authors":"G. Figari, V. Magnasco","doi":"10.1163/157404007782913417","DOIUrl":"https://doi.org/10.1163/157404007782913417","url":null,"abstract":"We improve a previously reported technique for interpolating available values of atomic or molecular frequency-dependent multipole polarizabilities and calculating the related dispersion constants. The improvement is provided by a simple formula allowing for an efficient selection of the frequencies involved (i.e. the frequencies implying numerical evaluations performed on the interpolated polarizability). It is shown that sensibly lower interpolative errors are obtained, so giving an enhanced accuracy in the subsequent calculation of the related dispersion constants.","PeriodicalId":101169,"journal":{"name":"Soft Computing Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76056296","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}
Pub Date : 2007-11-01DOI: 10.1163/157404007782913192
K. Mikkelsen
The focus is on homogeneous dielectric media models utilizing correlated electronic structure response methods for calculating time-dependent linear and nonlinear optical molecular porperties.
重点是利用相关电子结构响应方法计算随时间变化的线性和非线性光学分子特性的均匀介质模型。
{"title":"Homogenoues Solvent Models for Linear and Nonlinear Optical Properties","authors":"K. Mikkelsen","doi":"10.1163/157404007782913192","DOIUrl":"https://doi.org/10.1163/157404007782913192","url":null,"abstract":"The focus is on homogeneous dielectric media models utilizing correlated electronic structure response methods for calculating time-dependent linear and nonlinear optical molecular porperties.","PeriodicalId":101169,"journal":{"name":"Soft Computing Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74538718","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}
Pub Date : 2007-11-01DOI: 10.1163/157404007782913354
A. J. Sadlej
The possible origin of some discrepancy between the dipole polarizability of the sodium atom obtained from experimental studies and highly sophisticated atomic calculations, and its value computed by using 'molecular' methods of the electronic structure theory, is discussed. The extensive basis set saturation study shows that the earlier 'molecular' values are affected by the basis set deficiencies. The present scalar relativistic result calculated at the level of the coupled cluster (CCSD(T)) approximation is equal to 162.88 au and perfectly agrees with experimental (162.7 ± 0.8 au) and theoretical (162.6 ± 0.3 au, 163.06 au) atomic values. The present directly computed value also confirms the correctness of the earlier 'molecular' estimate (162.88 ± 0.6 au) obtained on the basis of extensive nonrelativistic CCSD(T) calculations.
{"title":"Dipole Polarizability of Sodium","authors":"A. J. Sadlej","doi":"10.1163/157404007782913354","DOIUrl":"https://doi.org/10.1163/157404007782913354","url":null,"abstract":"The possible origin of some discrepancy between the dipole polarizability of the sodium atom obtained from experimental studies and highly sophisticated atomic calculations, and its value computed by using 'molecular' methods of the electronic structure theory, is discussed. The extensive basis set saturation study shows that the earlier 'molecular' values are affected by the basis set deficiencies. The present scalar relativistic result calculated at the level of the coupled cluster (CCSD(T)) approximation is equal to 162.88 au and perfectly agrees with experimental (162.7 ± 0.8 au) and theoretical (162.6 ± 0.3 au, 163.06 au) atomic values. The present directly computed value also confirms the correctness of the earlier 'molecular' estimate (162.88 ± 0.6 au) obtained on the basis of extensive nonrelativistic CCSD(T) calculations.","PeriodicalId":101169,"journal":{"name":"Soft Computing Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75122775","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}
Pub Date : 2007-11-01DOI: 10.1163/157404007782913381
Arijit Bag, Prashant Manohar, S. Pal
In this article, we present analytical dipole moments and dipole polarizabilities of oxygen monofluoride and nitrogen dioxide using the recently developed constrained variational approach in Fock-space multi-reference coupled-cluster singles and doubles (CVA-FSMRCCSD) method. Both these molecules are important in atmospheric chemistry. The near-degeneracy in low-lying states of these molecules demands for MR description of the wavefunction. We also report our study of variation in the properties of oxygen monofluoride with respect to basis set. Benchmark results, wherever available, have been duly reported for comparison.
{"title":"Analytical Dipole Moments and Dipole Polarizabilities of Oxygen Mono-Fluoride and Nitrogen Dioxide: A Constrained Variational Response to Fock-Space Multi-Reference Coupled-Cluster Method","authors":"Arijit Bag, Prashant Manohar, S. Pal","doi":"10.1163/157404007782913381","DOIUrl":"https://doi.org/10.1163/157404007782913381","url":null,"abstract":"In this article, we present analytical dipole moments and dipole polarizabilities of oxygen monofluoride and nitrogen dioxide using the recently developed constrained variational approach in Fock-space multi-reference coupled-cluster singles and doubles (CVA-FSMRCCSD) method. Both these molecules are important in atmospheric chemistry. The near-degeneracy in low-lying states of these molecules demands for MR description of the wavefunction. We also report our study of variation in the properties of oxygen monofluoride with respect to basis set. Benchmark results, wherever available, have been duly reported for comparison.","PeriodicalId":101169,"journal":{"name":"Soft Computing Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85201875","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}
Pub Date : 2007-11-01DOI: 10.1163/157404007782913165
Masahito Nate, Hideaki Takahashi, A. Takebe, R. Kishi, Shin-ya Umezaki, M. Nakano
We investigate the chain length dependences of static polarizabilities (α) and second hyperpolarizabilities (γ) for one-dimensional hydrogen (H)-bonded chains composed of formamide from the viewpoint of cooperative effect of H-bonds. The α and γ values are calculated by the finite-field approach using the Hartree-Fock (HF), Moller-Presset perturbation theory (MP) and density functional theory (DFT) methods in order to clarify the electron correlation effects on the α and γ values of the H-bonded systems. The increase ratio of γ values per monomer for the increase of the number of monomers is found to be significantly enhanced compared to that of α values per monomer. This feature suggests the strong cooperative effects on γ originating in the interaction between the H-bonds and π-electrons of the monomers in the high-lying excited states mainly contributing to γ.
{"title":"Static Polarizabilities (α) and Second Hyperpolarizabilities (γ) of One-Dimensional Hydrogen-Bonded Formamides","authors":"Masahito Nate, Hideaki Takahashi, A. Takebe, R. Kishi, Shin-ya Umezaki, M. Nakano","doi":"10.1163/157404007782913165","DOIUrl":"https://doi.org/10.1163/157404007782913165","url":null,"abstract":"We investigate the chain length dependences of static polarizabilities (α) and second hyperpolarizabilities (γ) for one-dimensional hydrogen (H)-bonded chains composed of formamide from the viewpoint of cooperative effect of H-bonds. The α and γ values are calculated by the finite-field approach using the Hartree-Fock (HF), Moller-Presset perturbation theory (MP) and density functional theory (DFT) methods in order to clarify the electron correlation effects on the α and γ values of the H-bonded systems. The increase ratio of γ values per monomer for the increase of the number of monomers is found to be significantly enhanced compared to that of α values per monomer. This feature suggests the strong cooperative effects on γ originating in the interaction between the H-bonds and π-electrons of the monomers in the high-lying excited states mainly contributing to γ.","PeriodicalId":101169,"journal":{"name":"Soft Computing Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81257922","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}
Pub Date : 2007-11-01DOI: 10.1163/157404007782913291
Christine Neipert, Brian Space
In a recent work a novel, molecular dynamics (MD) based, theory was presented that provides a direct means to calculate the third order contributions to sum frequency vibrational spectroscopy (SFVS) at charged interfaces.[1] This contribution is described by a time correlation function (TCF) of the system's total hyperpolarizability (β) and dipole. A system's hyperpolarizability[2, 3, 4, 5] is difficult to calculate on the fly – no appropriate non-electronic structure (ES) techniques exist. In this work, such a model is developed for liquid water based on a formalism proposed previously.[1] The model is parametrized from and tested against, ab initio ES calculations. It was found that it is possible to reproduce the hyperpolarizability tensor of a gas phase water molecule and a water dimer accurately. Also, most relevant components of the hyperpolarizability derivative tensor of both the water and water dimer were also accurately fit, however, some elements were not able to be simultaneously reproduced. The model was also tested to assess whether or not it could reproduce the three non-zero condensed phase water hyperpolarizability tensor components. It was found that the model could capture two of the three relevant components.
{"title":"A Distributed Hyperpolarizability Model for Liquid Water","authors":"Christine Neipert, Brian Space","doi":"10.1163/157404007782913291","DOIUrl":"https://doi.org/10.1163/157404007782913291","url":null,"abstract":"In a recent work a novel, molecular dynamics (MD) based, theory was presented that provides a direct means to calculate the third order contributions to sum frequency vibrational spectroscopy (SFVS) at charged interfaces.[1] This contribution is described by a time correlation function (TCF) of the system's total hyperpolarizability (β) and dipole. A system's hyperpolarizability[2, 3, 4, 5] is difficult to calculate on the fly – no appropriate non-electronic structure (ES) techniques exist. In this work, such a model is developed for liquid water based on a formalism proposed previously.[1] The model is parametrized from and tested against, ab initio ES calculations. It was found that it is possible to reproduce the hyperpolarizability tensor of a gas phase water molecule and a water dimer accurately. Also, most relevant components of the hyperpolarizability derivative tensor of both the water and water dimer were also accurately fit, however, some elements were not able to be simultaneously reproduced. The model was also tested to assess whether or not it could reproduce the three non-zero condensed phase water hyperpolarizability tensor components. It was found that the model could capture two of the three relevant components.","PeriodicalId":101169,"journal":{"name":"Soft Computing Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79799531","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}
Pub Date : 2007-11-01DOI: 10.1163/157404007782913345
A. Avramopoulos, M. Papadopoulos
The linear and nonlinear optical (L&NLO) properties of the recently synthesized Xenon compounds HXeOH and HXeSH are studied. For this purpose a hierarchy of basis sets in connection with the widely used electron correlation methods, MP2, CCSD, CCSD(T), were employed in order to discuss the dipole moment, polarizability and first hyperpolarizability of these compounds. It was found that Xe insertion has a great effect on the hyperpolarizability of H2O and H2S. A significant electron correlation contribution was also observed, in particular for HXeSH. The strongly ionic character (H-Xe)+ (A-H)−, where A=O or S, of these compounds was elucitated by employing a natural bond orbital analysis. The enhanced NLO response of the studied species has been rationalized by employing a two-state model.
{"title":"The Effect of Xenon Insertion on the Linear and Non-Linear Optical Properties of HXeOH and HXeSH","authors":"A. Avramopoulos, M. Papadopoulos","doi":"10.1163/157404007782913345","DOIUrl":"https://doi.org/10.1163/157404007782913345","url":null,"abstract":"The linear and nonlinear optical (L&NLO) properties of the recently synthesized Xenon compounds HXeOH and HXeSH are studied. For this purpose a hierarchy of basis sets in connection with the widely used electron correlation methods, MP2, CCSD, CCSD(T), were employed in order to discuss the dipole moment, polarizability and first hyperpolarizability of these compounds. It was found that Xe insertion has a great effect on the hyperpolarizability of H2O and H2S. A significant electron correlation contribution was also observed, in particular for HXeSH. The strongly ionic character (H-Xe)+ (A-H)−, where A=O or S, of these compounds was elucitated by employing a natural bond orbital analysis. The enhanced NLO response of the studied species has been rationalized by employing a two-state model.","PeriodicalId":101169,"journal":{"name":"Soft Computing Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83847547","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}
Pub Date : 2007-11-01DOI: 10.1163/157404007782913228
B. B. Neto, M. B. Costa, A. E. D. A. Machado
Partial least squares (PLS) predictions for the first and second static hyperpolarizabilities (β and γ) of aniline octamer derivatives were calculated from AM1 values of the Homo-Lumo energy gap, the ground state dipole moment, the ionization potential, and the number of π-electrons. The calculations were performed for oligomers of the neutral forms of polyaniline (leucoemeraldine, emeraldine and pernigraniline) having donor (D) and/or acceptor (A) groups incorporated into their structure. The PLS estimated values are in good agreement with the β and γ values calculated at the AM1/CPHF level.
{"title":"Partial Least Squares Prediction of the Hyperpolarizabilities of Aniline Octamer Derivatives","authors":"B. B. Neto, M. B. Costa, A. E. D. A. Machado","doi":"10.1163/157404007782913228","DOIUrl":"https://doi.org/10.1163/157404007782913228","url":null,"abstract":"Partial least squares (PLS) predictions for the first and second static hyperpolarizabilities (β and γ) of aniline octamer derivatives were calculated from AM1 values of the Homo-Lumo energy gap, the ground state dipole moment, the ionization potential, and the number of π-electrons. The calculations were performed for oligomers of the neutral forms of polyaniline (leucoemeraldine, emeraldine and pernigraniline) having donor (D) and/or acceptor (A) groups incorporated into their structure. The PLS estimated values are in good agreement with the β and γ values calculated at the AM1/CPHF level.","PeriodicalId":101169,"journal":{"name":"Soft Computing Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82012824","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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