Trying to use \bigskip in the table and cannot prevent breaking table border lines

Question

as you could see in the topic: I try to effectively use \bigskip, \smallskip or \medskip in table, but my border lines are breaking whenever i try:

I am quite sure there must be solution for this, but cannot find anywhere what command should be added to prevent that situation. Any help will be much appreciated! :)

My MWE:

\documentclass[aps,physrev,showkeys,twocolumn,nofootinbib,floatfix]{revtex4-2}
\usepackage[polish]{babel}
\selectlanguage{polish}
\usepackage{polski}
\usepackage[table,xcdraw]{xcolor}
\usepackage{array,booktabs}
\usepackage{multirow}
\usepackage{tabularx}
\usepackage{setspace}
\newcommand\VRule[1][\arrayrulewidth]{\vrule width #1}


\begin{document}

\onecolumngrid
\newpage
\arrayrulecolor{yellow}
\begin{table}[htbp]

\begin{tabular}{ !{\color{red}\VRule[.5mm]} l    l !{\color{green}\VRule[.5mm]}  } \specialrule{.5mm}{2pt}{0cm}
\hspace{5mm} \textbf{Symbol} & \textbf{Opis} \bigskip \\
\hspace{5mm} $\mathrm{ a }$ \hspace{3cm} & --~połowa długości [długość] pęknięcia w próbce M(T) [CT]  \\ 
\hspace{5mm} $\mathrm{ BFS }$ & --~oznaczenie pozycji czujnika \\
\hspace{5mm} $\mathrm{ CC }$ & --~zamykanie się pęknięcia  \\ \specialrule{2pt}{0pt}{0pt}
\end{tabular}
\end{table}
\twocolumngrid

\end{document}

Answer 1

In sense on my answer on your next question Table border problem you can write your table as follows:

\documentclass[aps,physrev,showkeys,twocolumn,nofootinbib,floatfix]{revtex4-2}
\usepackage[polish]{babel}
\selectlanguage{polish}
\usepackage{polski}
\usepackage[table,xcdraw]{xcolor}
\usepackage{tabularray}


\begin{document}

\onecolumngrid
\newpage
    \begin{table}[htbp]
\begin{tblr}{hline{1,Z} = {0.5mm,yellow}, 
             vline{1} = {0.5mm, red},  vline{Z} = {0.5mm, green},
             colspec = {Q[l, mode=math, leftsep =4mm, wd=9em] Q[l]},
             row{1} = {font=\bfseries, mode=text},
             row{1-2} = {abovesep=4mm}
             }
Symbol              &   Opis                                                    \\ 
\mathrm{a}          & -- połowa długości [długość] pęknięcia w próbce M(T) [CT] \\
\mathrm{BFS}        & -- oznaczenie pozycji czujnika                            \\
\mathrm{CC}         & -- zamykanie się pęknięcia                                \\ 
\mathrm{CMOD}       & -- \dots                                                  \\
\mathrm{COD[CTOD]}  & -- \dots                                                  \\
\end{tblr}
    \end{table}
\twocolumngrid

\end{document}

Answer 2

Okay i found useful clue here: https://latex.org/forum/viewtopic.php?t=10224 After \\ we can put value of vertical spacing in: [], for example \\ [2cm] So this is kind of solution, but maybe we can improve it. Does LaTeX have any command for specific height of one row? Of course I can type value, but maybe there is more convenient method that will fit to any type of document class...