1). In Page 4, the reason for selec

1). In Page 4, the reason for selection of methods should be provided for readers; and the benchmark of some popular methods should be summarized from related studies.2). In the statement '.... the introduction of carbon-carbon double bonds into the parent molecules improves the third-order nonlinear-optical properties.', more details should be provided for readers, otherwise, it will not be acceptable for general practice.3). I suggest the conclusion part should be better organized and even rewritten, to deliver a brief logics for general readers.4). The grammar mistakes should be carefully checked; and many figures should be refined.