Molecular beam photoelectron spectroscopy and femtosecond intramolecular dynamics of H2O+ and D2O+

Abstract

Articles you may be interested inHigh resolution photoelectron spectroscopy and femtosecond intramolecular dynamics of H2CCO+ and D2CCO+ J. Chem. Phys. 99, 2520 (1993); 10.1063/1.465215High resolution photoelectron spectroscopy and femtosecond intramolecular dynamics of H2CO+ and D2CO+The 584 A photoelectron spectra of supersonic molecular beams of H 2 0 and D 2 0 have been obtained with improved resolution. The spectroscopic constants of the X 2 Bland A 2A I state ions, including w? , x? I , w~, X~2' and X?l' are reported. For the first two electronic states of the ion, precise line splittings were evaluated with a least squares fitting procedure, employing sums of empirical instrument response functions and a linear background. A simulation of the vibrational manifolds of the B 2 B2 state ions with combination progressions in the symmetryallowed modes VI and V 2 failed to reproduce the diffuse photoelectron bands observed for both H 2 0 and D 2 0. Autocorrelation functions were calculated from the photoelectron bands of all three electronic states. The B 2Bl state correlation functions exhibit ultrafast decay, occurring on a 10-14 s time scale. The V 2 motion appears to define the decay in the correlation function.This behavior supports a previously proposed B 2B2-A 2AI curve-crossing model for the nonradiative relaxation ofthe B 2B2 state ions.the 600-1000 A region revealed that the threshold for frag-6928

Core Excitation and De-excitation Spectroscopies of Free Atoms and Molecules

“…2b 2 ð0; 0Þ excitation with the gas cell and under Doppler-free conditions. The X band is dominated by the ðv 00 1 ; 0Þ progression corresponding to the symmetric stretching with a spacing of 398 meV 89) and starting at 12.62 eV. In the Doppler-free spectrum, it is clear that the vibrational progression ðv 00 1 ; 1Þ, starting at the energy of 12.78 eV is also excited.…”

“…In the Doppler-free spectrum, it is clear that the vibrational progression ðv 00 1 ; 1Þ, starting at the energy of 12.78 eV is also excited. In the gas-cell spectrum, the resolution is not sufficiently high for us to say whether the A band contains more than one vibrational progression, whereas in the Doppler-free spectrum, it is clear that only the bending progression ð0; v 00 2 Þ with a frequency of 108 meV 89) is present; the stretching mode has a frequency of 439 meV and is not present.…”

“…The spacings of the stretching and bending modes in this band are 368 and 198 meV, respectively. 89) Thus, if only one of the two modes was excited, we could see the progression. It seems the reason why the vibrational structure is not clearly resolved is because of multimode vibrational excitations in the final states.…”

High resolution photoelectron spectroscopy and femtosecond intramolecular dynamics using supersonic molecular beams

“…In the preceding section, we mentioned the Born-Oppenheimer (BO) approximation 17 which forms the base of our Franck-Condon factor analysis and selections rules. The BO approximation is also known as the adiabatic approximation.…”

“…To interpret the photoelectron spectrum obtained, one can use the selection rules based on the Born-Oppenheimer approximation 17 (which enables us to treat the electronic and nuclei parts of molecular motions separately), the dipole approximation (for electronic transition) and the harmonic (for vibrational transition) approximation to rule out those inactive vibrational modes. For the details of the selection rules involved in photoelectron spectroscopy, Reference 8 is recommended.…”