Full Configuration Interaction Energies, Geometries, and Quartic Force Fields of the Nitrenium Ion

[img]PDF - Authorized users only
Language: English
214Kb
Title:Full Configuration Interaction Energies, Geometries, and Quartic Force Fields of the Nitrenium Ion
Creators:
Van Huis, Timothy J.
Leininger, Matthew L.
Sherrill, C. David
Schaefer, Henry F.
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 63, 8, pp. 1107-1142
Uncontrolled Keywords:Quartic force fields, Nitrenium ion, Ionization potentials, Full configuration interaction

Abstract

Benchmark configuration interaction energies, geometries, dipole moments, and harmonic vibrational frequencies are obtained for four low-lying electronic states of NH<sub>2</sub><sup>+</sup> and for X<sup>2</sup>B<sub>1</sub> NH<sub>2</sub> by solving the electronic Schrodinger equation exactly within a double-ζ plus polarization (DZP) basis set and restricting the nitrogen 1s-like core orbital to remain doubly occupied. In addition, full quartic force fields have been determined, and sets of anharmonic spectroscopic constants and fundamental frequencies are reported for the ã <sup>1</sup>A<sub>1</sub> state of NH<sub>2</sub><sup>+</sup>. Vertical and adiabatic ionization potentials of NH<sub>2 </sub>are also determined exactly within a DZP basis. The capability of less-complete electron correlation treatments to match these exact, full configuration interaction (full CI) results is assessed. The efficacy of obtaining anharmonic force fields at nonstationary geometries is also examined, and in agreement with previous work, it is found that the self-consistent field method can provide high quality cubic and quartic force constants when they are evaluated at the full CI equilibrium geometry. Both the CCSD(T) and CASSCF-SOCI methods provide geometric and spectroscopic data in excellent agreement with the Full CI results and are competitive in their reliability with more expensive procedures (<i>e.g.</i> CISDTQ). The second <sup>1</sup>A<sub>1</sub> state in <i>C</i><sub>2v</sub> symmetry is predicted by the TZ2P(f,d) CASSCF-SOCI wavefunction to be linear (thus properly labeled as c<sup>1</sup>Σ<sub>g</sub><sup>+</sup>), even though it is found to be quasilinear at the DZP full CI level.

Title:Full Configuration Interaction Energies, Geometries, and Quartic Force Fields of the Nitrenium Ion
Creators:
Van Huis, Timothy J.
Leininger, Matthew L.
Sherrill, C. David
Schaefer, Henry F.
Uncontrolled Keywords:Quartic force fields, Nitrenium ion, Ionization potentials, Full configuration interaction
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:63
Number:8
Page Range:pp. 1107-1142
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19981107UNSPECIFIED
ID Code:1369
Item Type:Article
Deposited On:06 Feb 2009 17:09
Last Modified:06 Feb 2009 16:09

Citation

Van Huis, Timothy J.; Leininger, Matthew L.; Sherrill, C. David; Schaefer, Henry F. (1998) Full Configuration Interaction Energies, Geometries, and Quartic Force Fields of the Nitrenium Ion. Collection of Czechoslovak Chemical Communications, 63 (8). pp. 1107-1142. ISSN 0010-0765

Repository Staff Only: item control page