# Slow and rapid molecular passages

A time-dependent Hamiltonian supplies both excitation and field-to-matter work. The same final change has different responses at different durations. No environment, dissociation continuum or biological repair system is represented. The alpha scan is a response experiment, not a demonstrated viable field history.

A moving cursor shows the computed H2 excited population and matching molecular energy change and background work. The population scale is fixed across slow and rapid cases.

## Duration 0.1 atomic times

Actual two-electron H2 evolution, fixed nuclei, cc-pVDZ determinant basis; final alpha +1%. Energy and norm checks accompany each solve.

First: Elapsed passage coordinate -0.8 atomic times (-1.94e-17 s); alpha / initial = 1.000000; excited population = 0.

Last: Elapsed passage coordinate +0.8 atomic times (+1.94e-17 s); alpha / initial = 1.010000; excited population = 8.06e-05.

## Duration 10 atomic times

Actual two-electron H2 evolution, fixed nuclei, cc-pVDZ determinant basis; final alpha +1%. Energy and norm checks accompany each solve.

First: Elapsed passage coordinate -80 atomic times (-1.94e-15 s); alpha / initial = 1.000000; excited population = 2.22e-16.

Last: Elapsed passage coordinate +80 atomic times (+1.94e-15 s); alpha / initial = 1.010000; excited population = 8.8e-13.

## Duration 100 atomic times

Actual two-electron H2 evolution, fixed nuclei, cc-pVDZ determinant basis; final alpha +1%. Energy and norm checks accompany each solve.

First: Elapsed passage coordinate -800 atomic times (-1.94e-14 s); alpha / initial = 1.000000; excited population = 2.22e-16.

Last: Elapsed passage coordinate +800 atomic times (+1.94e-14 s); alpha / initial = 1.010000; excited population = 0.