export declare const FREQUENCY_UNITS: readonly ["THz", "eV", "meV", "cm^-1", "Ha"];
export type FrequencyUnit = (typeof FREQUENCY_UNITS)[number];
export declare const MD_FREQUENCY_UNITS: readonly ["THz", "cm^-1"];
export type MdFrequencyUnit = (typeof MD_FREQUENCY_UNITS)[number];
export declare const frequency_unit_per_thz: (unit: FrequencyUnit) => number;
export declare function convert_frequencies(frequencies: number[], to_unit?: FrequencyUnit, from_unit?: FrequencyUnit): number[];
export declare const parse_frequency_unit: (unit: unknown) => FrequencyUnit | null;
export declare const frequency_unit_label: (unit: string) => string;
export declare const TIME_UNIT_TO_THZ: Record<string, number>;
export declare const thz_per_inverse_time: (time_unit: string) => number | undefined;
export declare const md_frequency_factor: (time_unit: string, frequency_unit: MdFrequencyUnit) => number | null;