P beg

p_beg sets the target pressure, in bar, for the barostat at the beginning of a molecular dynamics simulation. The target pressure evolves with time like this:

[math]\displaystyle{ P = P_\text{beg} + \frac{i_\text{step}}{N_\text{steps}} (P_\text{end} - P_\text{beg}), }[/math]

where [math]\displaystyle{ i_\text{step} }[/math] is the current time step and [math]\displaystyle{ N_\text{steps} }[/math] is the total number of time steps in the simulation.

Summary

Summary for p_beg keyword

Required/optional	Type	Accepted values	Default	See also
Optional	Real	Any positive real	1.	barostat, p_end, tau_p, gamma_p

Example

barostat = "berendsen"
barostat_sym = "iso"
p_beg = 10. # in bar
p_end = 10. # in bar
tau_p = 100. # in fs
gamma_p = 10. # in units of the inverse compressibility of water