64 research outputs found
Ortho-para transition in molecular hydrogen
The radiative ortho-para transition in the molecular hydrogen is studied.
This highly forbidden transition is very sensitive to relativistic and subtle
nonadiabatic effects. Our result for the transition rate in the ground
vibrational level \Gamma(J=1\to J=0) = 6.20(62)\cdot 10^{-14} \iyr is
significantly lower in comparison to all the previous approximate calculations.
Experimental detection of such a weak line by observation of, for example, the
cold interstellar molecular hydrogen is at present unlikely.Comment: 4 pages, submitted to Phys. Rev.
Nonadiabatic corrections to rovibrational levels of H
The leading nonadiabatic corrections to rovibrational levels of a diatomic
molecule are expressed in terms of three functions of internuclear distance:
corrections to the adiabatic potential, the effective nuclear mass, and the
effective moment of inertia. The resulting radial Schr\"odinger equation for
nuclear motion is solved numerically yielding accurate nonadiabatic energies
for all rovibrational levels of H molecule in excellent agreement with
previous calculations by Wolniewicz.Comment: 14 page
Nonadiabatic corrections to the wave function and energy
Nonadiabatic corrections in molecules composed of a few atoms are considered.
It is demonstrated that a systematic perturbative expansion around the
adiabatic solution is possible, with the expansion parameter being the
electron-nucleus mass ratio to the power 3/4. Closed form formulae for the
leading corrections to the wave function and to the energy are derived. Their
applicability is demonstrated by a comparison of numerical results for the
hydrogen molecule with the former nonadiabatic calculations and the
experimental values. Good agreement with the recent experiment is achieved for
the ground state dissociation energy of both H and D.Comment: 8 pages, to be published in J. Chem. Phy
APPLICATION OF EXPLICITLY CORRELATED GAUSSIANFUNCTIONS TO LARGE SCALE CALCULATIONS ONSMALL ATOMS AND MOLECULES
Exponentially Correlated Gaussian wave functions are applied to variational calculations of thetotal electronic energy of several a few-electron atomic and molecular systems. It is shown thatthis powerful approach enables to obtain extremely accurate results not only for two-electronsystems but also for three- and four-electron atoms and molecules.Pozna
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