ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Multireference configuration interaction calculations of the low-lying electronic states of ClO2 (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 96 (1992), S. 8948-8961 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Using extensive internally contracted multireference configuration interaction wave functions and large basis sets, near-equilibrium potential energy functions for the first four doublet electronic states (X 2B1, 2B2, 2A1, and A 2A2 ) of OClO and the X 2A‘ electronic state of ClOO have been calculated. Electric dipole moment functions have also been computed for the ground states of both isomers. Spectroscopic constants derived for the X and A states of OClO, as well as for the X state of ClOO, are compared to the available experimental data, and predictions for the other states are made. In agreement with previous assumptions about the photodissociation of OClO, strong interactions between the first three excited electronic states in the Franck–Condon region of the A←X transition are indicated from cuts of the potential energy surfaces. In particular, the experimentally observed predissociation of the A 2A2 state is proposed from this work to proceed initially by an interaction with the close-lying 2A1 state. Additionally, the calculated asymmetric stretch potential for the A 2A2 state of OClO does not show evidence of a double minimum as has been previously proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.462253
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Submillimeter wave spectroscopy of XeH+ and XeD+ (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 2352-2360 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The J=0–1 rotational transition of XeH+ and the J=1–2 transition of XeD+, which both occur near 390 GHz, have been studied by microwave absorption spectroscopy. For each of these all nine naturally occurring stable isotopes of xenon were detected. The magnetic hyperfine structure for the 129Xe forms and the electric quadrupole–magnetic hyperfine structure of both 131Xe forms were fully resolved and analyzed to determine the CI and eQq0 constants. The scaled spin–rotation parameter CI/(gIB) is found to be practically identical in XeH+ and HI, as it is also in the isoelectronic pair KrD+ –DBr/HBr. The available magnetic field was too small to resolve the rotational Zeeman effect, but the rotational g factor of XeH+ was estimated from Zeeman broadening. The mass-independent Dunham parameters U01, ΔH01, and ΔXe01 were determined from the very accurate microwave frequencies combined with higher order Dunham coefficients from published Fourier-transform infrared (FTIR) spectroscopy of XeH+ . Although it was not practical to observe XeH+ or XeD+ in excited vibrational states, we were able to detect the J=0–1 (v=1) transition of ArD+ .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.460941
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Spectroscopic properties of OCS and OCCl+ by Møller–Plesset perturbation theory and configuration interaction (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 431-441 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Ab initio calculations have been carried out on the stretching potential energy surfaces of OCS and the isoelectronic positive ion OCCl+. The methods used included fourth order Møller–Plesset perturbation theory with single, double, and quadruple substitutions (MP4SDQ), singles and doubles configuration interaction (CI-SD), and the latter with the addition of a size-consistency correction [designated CI-SD(s)]. Identical calculations were also carried out on the diatomics CO, CS, and CCl+, and these results were used to correct the CI-SD(s) potential energy functions of OCS and OCCl+. Stretching vibrational band origins have been calculated variationally for both OCS and OCCl+, and those for OCS obtained from the corrected CI-SD(s) potential function are within 0.4% of experiment for transitions up to 5000 cm−1. The ground state rotational constant of OCCl+ is predicted to be 5955±15 MHz, while the band origins of the ν1 and ν3 stretching fundamentals are predicted to lie at 793(10) and 2282(20) cm−1, respectively. Electric dipole moments have been calculated from the CI-SD wave functions, and rotationless dipole moment matrix elements have been derived from the analytical dipole moment functions and the vibrational wave functions obtained from the variational calculations. The ν3 band of OCCl+ is predicted by CI-SD to be fairly strong with a band strength of 1490 cm−2 atm−1, while the ν1 band is weaker by more than 1 order of magnitude.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.460358
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The potential energy and dipole moment surfaces of NF2 and O−3 by complete active space self-consistent field (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 5020-5028 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Three-dimensional potential energy and dipole moment surfaces have been calculated for the 25 electron radicals NF2 and O−3 in their 2B1 ground electronic states by the complete active space self-consistent field (CASSCF) method with basis sets of 87 (NF2) and 99 (O−3) contracted Gaussian-type orbitals. Spectroscopic constants have been calculated from the analytical potential energy functions for each species, and the results for NF2 are compared to the available experimental data. Predictions of the rotational and rotational–vibrational spectra of O−3 have been made by comparison to the NF2 results. Vibrational band origins have been calculated by perturbation theory and also variationally in a basis of distributed Gaussian functions. Rotationless dipole moment matrix elements and vibrational band intensities have been determined from the CASSCF dipole moment functions. The fundamental vibrational band origins and intensities of O−3 are predicted to be 979 cm−1/0.87 cm−2 atm−1 (ν1), 565 cm−1/17.8 cm−2 atm−1 (ν2), and 739 cm−1/2620 cm−2 atm−1 (ν3). Smaller basis set calculations of the first three excited electronic states of O−3 have also been carried out, and the results are compared to previous photodissociation experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.458639
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Spectroscopic properties of the X 1Σ+ and a 3Π electronic states of CF+, SiF+, and CCl+ by multireference configuration interaction (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 1889-1894 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Potential energy and dipole moment functions have been calculated using multireference configuration interaction (MRCI) techniques for CF+, SiF+, and CCl+ in their ground 1Σ+ and first 3Π electronic states with large Gaussian basis sets. Where experimental data is available, the MRCI values of re and ωe are accurate to within 0.006 A(ring) and 7 cm−1, respectively. The Te values for the a 3Π–X 1Σ+ transitions for CF+, SiF+, and CCl+are calculated to be 4.77±0.05 eV, 4.78±0.05 eV, and 3.19±0.05 eV (3.16 eV), respectively (experimental value in parentheses). Rotational and vibrational spectroscopic constants are also predicted for all three species in the 3Π state. Infrared transition probabilities have been calculated from the MRCI potential energy and dipole moment functions. Intense infrared transitions are predicted for all three species in both their ground and first excited state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.459066
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Configuration interaction potential energy and dipole moment functions for thirteen 22 electron diatomics (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 6061-6068 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Singles and doubles CI with a large Gaussian basis set has been used to calculate potential energy and dipole moment functions for the following series of 22 electron diatomics: AlF, SiF+, AlO−, SiO, PO+, SiN−, PN, NS+, CP−, CS, CCl+, BS−, and BCl. A size consistency correction was applied to the CI-SD potentials to obtain results designated CI-SD(s). The calculations on the neutral species were used to correct the ab initio values of re and ωe for the ions, resulting in agreement with experiment to within 0.002 A(ring) for re and 10 cm−1 for ωe in those cases where high resolution spectroscopic results were available (CCl+, SiF+, and PO+), and predictions for the spectra of the other five ions are expected to be of similar accuracy. The CI-SD(s) corrected values for CCl+, SiF+, and PO+ are somewhat closer to experiment than our earlier corrected MP4SDQ values, and the problems with RHF→UHF instability encountered in the MP4SDQ calculations of vibrational constants of certain species do not appear to affect the present work. Dipole moment matrix elements have been calculated from the CI-SD dipole moment functions and CI-SD(s) potential functions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.458378
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Spectroscopic constants and dipole moment functions of the 22 electron dications SiNe++, PF++, SO++, NCl++, and CAr++ (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 3528-3535 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The potential energy functions and spectroscopic constants of a series of eighteen 22 electron diatomic molecules with charge −1, 0, +1, and +2 have been obtained using version 1 of the coupled electron pair approximation (CEPA-1) with a Gaussian basis set of 101 functions, containing both f orbitals and diffuse s and p orbitals. All of these except the negative ions have also been treated by singles and doubles configuration interaction (CI-SD) and by the latter including a size consistency correction [CI-SD(s)] with a slightly smaller basis set (93 functions) that omitted the diffuse s and p functions. Both methods [CEPA-1 and CI-SD(s)] produce values of re and ωe for the neutral and monocation species that give deviations from experiment that are both small and smoothly varying across the series. Corrections based on these deviations have been applied to the re and ωe values of the spectroscopically unknown dications, SiNe++, PF++, SO++, NCl++, and CAr++, which possess either great kinetic stability, or in some cases, even thermodynamic stability, as published ab initio calculations have already demonstrated. Our estimated uncertainties for the corrected re and ωe values are different for the five dications, depending upon the available spectroscopically known comparison species and the consistency achieved between methods, but in the most favorable case (PF++) they are ±0.002 A(ring) and ±10 cm−1. The dipole moment functions of the doubly charged ions have been calculated for the first time (using CI-SD) and used to estimate the intensities of the rotational and vibrational spectra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.460855
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Theoretical dipole moment functions involving the a 3Π and a' 3Σ+ states of carbon monoxide (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 5029-5036 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Potential energy and dipole moment functions have been calculated for the first two excited electronic states of CO by several ab initio methods using large Gaussian basis sets. Similar calculations on the ground state have also been performed to provide a basis for comparison. The types of calculations on the a 3Π state included complete active space self-consistent field (CASSCF), single reference single and doubles configuration interaction (CI-SD) including a size consistency correction [CI-SD(s)], quadratic CI-SD (QCI-SD), and quadratic CI-SD including the effects of triple excitations [QCI-SD(T)], and version 1 of the coupled electron pair approximation (CEPA-1).The best calculated dipole moment functions for the a 3Π state have been found to be consistent with earlier theoretical results with respect to shape (slope, μ'e), and also more accurate in predicting the equilibrium value μe. Theoretical dipole moment functions for the a' 3Σ+state are presented for the first time, at the CI-SD, CI-SD(s), and CASSCF levels of approximation. The first two of these yield estimates of μe that are in very good agreement with that derived from the analysis of perturbations in the molecular beam electric resonance (MBER) Stark effect of the a 3Π state. The (a–a') electronic transition moment has also been calculated at the CASSCF and CI-SD levels. Our CASSCF value of 0.23 D (v‘=4, v'=0) compares well with values derived from the MBER Stark effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.458640
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    An ab initio study of the 24 electron radicals PF, SO, NCl, SF+, ClO+, SiF−, PO−, NS−, and CCl− in their X 3∑− electronic states (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 1876-1888 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The potential energy functions (PEFs) of the X 3∑− states of PF, SO, NCl, SF+, ClO+, SiF−, PO−, NS−, and CCl− have been calculated by several ab initio methods using a basis set of 101 contracted Gaussian-type orbitals. The methods used included fourth order Møller–Plesset perturbation theory with single, double, and quadruple substitutions (MP4SDQ), singles and doubles configuration interaction (CI-SD), version 1 of the coupled electron pair approximation (CEPA-1), and complete active space self-consistent field (CASSCF). The CI-SD PEFs were very similar to those calculated by CEPA-1 when a size-consistency correction was added to the CI-SD total energies, and these results were designated CI-SD(s). The results for the neutral radicals are compared to the available experimental data, and predictions of the rotational and vibrational spectra of the ions have been made. Dissociation energies have been calculated for all nine species at the MP4SDTQ (MP4SDQ including triple substitutions) level of approximation, which also yielded MP4SDTQ ionization potentials for SF and ClO and electron affinities of SiF, PO, NS, and CCl. All of the negative ions are predicted to be stable with respect to loss of an electron by at least 20 kcal/mol. Electric dipole moment functions have also been computed for each species by CI-SD, CEPA-1, and CASSCF. Molar integrated IR absorption intensities for the fundamental transitions are predicted to be (in cm2mol−1) 15 860 (PF, CEPA-1), 1890 (SO, CASSCF), 5995 (NCl, CEPA-1), 7235 (SF+, CEPA-1), 1205 (ClO+, CASSCF), 20 070 (SiF−, CEPA-1), 20 390 (PO−, CASSCF), 90.0 (NS−, CASSCF), and 22 600 (CCl−, CEPA-1).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.459065
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Predictions of the rotational and vibrational spectra of SiF+, PO+, and NS+ by Møller–Plesset perturbation theory (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 4929-4944 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In order to predict accurately the spectroscopic constants of SiF+, PO+, and NS+, calculations at the MP4SDQ level have been carried out for the following series of 22 electron diatomics: AlF, SiF+, SiO, PO+, PN, NS+, CS, CCl+, and BCl. Two basis sets, one containing 66 contracted Gaussian-type orbitals and the other with 93, have been employed for each of the nine molecules to calculate potential energy functions and spectroscopic constants. The ab initio re and ωe values for the three ions whose high resolution spectra were not previously observed were corrected by reference to deviations between theory and experiment for the other six species, whose spectra were already well known. The dipole moments and electric field gradients of each species at the equilibrium bond distance were calculated at the CI-SD level, and their dissociation energies were found to be predicted well by MP2 and very well by MP4SDTQ calculations. In order to understand better the differences between the spectral predictions of the two basis sets, re and ωe of the well known first row analogs BF, CF+, CO, NO+, and N2 were computed at the MP4SDQ level with a series of five basis sets of increasing flexibility. Using the current prediction for SiF+ we have recently located its rotational spectrum, extensive measurements of which will be published separately.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.455636
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...