TITLE

Vacuum ultraviolet pulsed field ionization study of ND3: Accurate thermochemistry for the ND2–ND2+ and ND3–ND3+ system

AUTHOR(S)
Qian, X. -M.; Lau, K. -C.; He, G. Z.; Ng, C. Y.; Hochlaf, M.
PUB. DATE
May 2004
SOURCE
Journal of Chemical Physics;5/8/2004, Vol. 120 Issue 18, p8476
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The dissociation of energy-selected ND3+ to form ND2++D near its threshold has been investigated using the pulsed field ionization-photoelectron (PFI-PE)-photoion coincidence method. The breakdown curves for ND3+ and ND2+ give a value of 15.891±0.001 eV for the 0 K dissociation threshold or appearance energy (AE) for ND2+ from ND3. We have also measured the PFI-PE vibrational bands for ND3+(X;v2+=0, 1, 2, and 3), revealing partially resolved rotational structures. The simulation of these bands yields precise ionization energies (IEs) for ND3+ X(0,v2+=0–3,0,0)←ND3 X(0,0,0,0). Using the 0 K AE (ND2+) and IE(ND3)=10.200±0.001 eV determined in the present study, together with the known 0 K bond dissociation energy for ND3 [D0(D–ND2)=4.7126±0.0025 eV], we have determined the D0(ND2+–D), IE(ND2), and 0 K heat of formation for ND2+ to be 5.691±0.001 eV, 11.1784±0.0025 eV, and 1261.82±0.4 kJ/mol, respectively. The PFI-PE spectrum is found to exhibit a steplike feature near the AE(ND2+), indicating that the dissociation of excited ND3+ at energies slightly above the dissociation threshold is prompt, occurring in the time scale ≤10-7 s, as observed for the NH3 system. The available energetic data for the NH2–NH2+ and NH3–NH3+ system are found to be in excellent accord with those for the ND2–ND2+ and ND3–ND3+ system after taking into account the zero-point vibrational energy corrections. This finding indicates that the thermochemical data for these two systems are reliable with well-founded error limits. © 2004 American Institute of Physics.
ACCESSION #
12879452

 

Related Articles

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics