X- {sup 3}B{sub 1}, a- {sup 1}A{sub 1}, b- {sup 1}B{sub 1}, and c- {sup 1}A{sub 1} electronic states of CH{sub 2}

Journal Article · Thu May 09 04:00:00 EDT 1996 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/jp953150i· OSTI ID:263221

Yamaguchi, Yukio; Sherrill, C D; Schaefer, III, H F ^[1]

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1. Univ. of Georgia, Athens, GA (United States)

Four electronically low-lying states of CH{sub 2} have been investigated systematically by using ab initio electronic structure theory. Self-consistent-field (SCF), two-configuration self-consistent field (TCSCF), complete active space self-consistent-field (CASSCF), configuration interaction with single and double excitations (CISD), and CASSCF second-order configuration interaction (SOCI) levels of theory were employed with nine different basis sets. Special emphasis is placed on the second and third excited states. The third excited state (c- {sup 1}A{sub 1}) is of particular theoretical interest because it is represented by the second root of TCSCF, CASSCF, TCSCF-CISD, and CASSCF-SOCI wave functions. It is confirmed in this study that the four low-lying states of CH{sub 2} all have bent structures. For these four states total energies and physical properties including dipole moments, harmonic vibrational frequencies, and associated infrared (IR) intensities were determined and compared with available experimental values. At the CISD level with the largest basis set, the triple-{zeta} plus triple polarizations with two higher angular momentum and two diffuse functions basis set [TZ3P(2f,2d)+2diff], the dipole moments are determined. 55 refs., 8 tabs.

• DOE Contract Number: FG05-94ER14428
• OSTI ID: 263221
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 19 Vol. 100; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
66 PHYSICS
99 GENERAL AND MISCELLANEOUS
ALKENES
BOND ANGLE
BOND LENGTHS
CALCULATION METHODS
DIPOLE MOMENTS
ELECTRONIC STRUCTURE
EXCITED STATES
GROUND STATES
INFRARED SPECTRA
METHYLENE RADICALS
MOLECULAR MODELS
THEORETICAL DATA
VIBRATIONAL STATES