Let $f : \mathbb{R} \to \mathbb{C}$ be a smooth and bounded function.


If we denote by $\{ H_n(x) \}$ the sequence of normalized Hermite polynomials, then the Hermite expansion of $f$ is defined as
\begin{equation}
\sum_{n=0}^\infty d_n H_n(x)
\end{equation}
where
\begin{equation}
d_n=\frac{1}{\sqrt{2\pi}n!}\int_{\mathbb{R}}f(x)H_n(x)e^{-x^2/2}dx
\end{equation}

According to the following link : https://mathoverflow.net/questions/29384/convergence-of-orthogonal-polynomial-expansions

the Hermite expansion converges uniformly to $f$ if $\lVert Hf \rVert_{L^2} < \infty$.

However, if I just assume that $f$ is smooth and bounded, can I still say something about convergence of its Hermite expansion?

I tried to look for references myself, but cannot find anything relevant.

Could anyone please help me?