if($('.accordion').length){
	$('<script />', {
		id: 'script',
		src: 'http://url.goes/here.js'
	}).appendTo('body');
};

I like to do this by registering my scripts in my functions.php using wp_register_script(). Then when the element which requires that script asset is present use the wp_enqueue_script() function to make sure that it loads. http://codex.wordpress.org/Function_Reference/wp_register_script

For example: in functions.php:

wp_register_script( 'jquery-bigtarget', 'http://url.to/jquery.bigtarget.1.0.1.js', false, false, true );

inside some IF statement:

if ( $this ) wp_enqueue_script('jquery-bigtarget);

I like to keep all my initializations in my main script.js file, so there is a nice way to put the init there but to render it useless when the necessary asset doesn't load.

if ( if ( $.isFunction($.fn.bigTarget) ) { code goes here }